First of all WordPress is a FREE AND provides excellent Search Engine Optimization (SEO), WordPress SEO by Yoast is one the best WordPress SEO plugin that help to get traffic and boost up search engine rank.

WordPress is very user friendly, and help you to mange content without  knowing programming language and using developers tools like Dreamweaver. On top of that you can extend your website features without hiring a web developer by implementing different themes and Plugins. If you want to extend your website,  you can get WordPress Developers support on line because there are lots of blogs provide Free tutorials and support online, all you have to Search on Google. Even Hosting companies like provide free help and support on WordPress powered sites.

[Resource: why-use-wordpress-to-power-your-small-business-website]

Today I am trying to compile a list of Plugins that help you to manage and have a powerful access control system by using WordPress, Although Drupal and Joomla provide you these features but now you can implement these features on your WordPress powered website.

On the following list of articles you can find how to create Multisite and manage your Network on WordPress.

• How to Managing Your WordPress Multi Sites (22.9)
• How to Get Posts from all Blogs in Multi Site Network (21.4)
• How to do Domain Mapping Without a Plugin in MultiSite Network (19.1)
• Free Download Plugins and Themes From WordPress Multi Site User (WPMU) (18.8)
• WordPress Plugins for Multisite Network Management (18.4)

WordPress Premium Content
Professional domain mapping
Open Source Training teaches people how to use Joomla, Drupal and WordPress.

Access Control in WordPress with Plugins

There are different WordPress Plugins that help you to have a control over your users and their contents. I am going to provide the best WordPress plugins for Access control to manage Content and users roles:

Advanced Access Manager

Advanced Access Manager is very powerful and flexible Access Control tool for your WordPress website. It supports Single WordPress installation and Multisite setup.

Detail

White Label Branding for WordPress

Are you a WordPress developer or a Web Designer who uses WordPress to develop websites for your clients? Have you ever wished that it was easier to customize the menu’s and logo’s in WordPress and to decide which menu’s the users have access to? With White Label Branding for WordPress you can do exactly this. Take full control over the branding in wp-admin and decide who has access to what features. With the latest version of White Label Branding you have the ultimate tool for customizing WordPress admin and your login screen.

Live preview | Detail

Userbase Access Control

Adds user access control via admin defined user groups on a per page level.

Features include:

• Access group creation
• User group assigning
• Redirect un-logged in user to defined login page
• Redirect public users to login page.
• Redirect Logged in users to Access denied/upgrade notice page

Detail By David Cramer| One to Many Relationship Tutorial in DB-Toolkit

WordPress Access Control

Detail By Brandon Wamboldt

Private! WordPress Access Control Manager

The configuration is as simple as powerful and the best of all: It’s incredible fast – you will not notice any differences from your standard installation to running a fully protected blog. It does not modify your roles, capabilities and it does not need new tables or adds queries to your normal pages.

Detail By Oliver Sperke

Simple Access Control

This plugin allows authors to restrict the users’s access to individual pages, posts and menu items based on the user’s logged in status.

Features for Authors

• You can restrict pages and posts while editing by using the “Simple Access Control” widget.
• You can set the message displayed when a visitor accesses a locked page using the “Simple Access Control” item in the Settings menu
• The locked status is shown in the admin page and post lists
• a “Loggedin Text” widget is available that only displays text to logged in users
• You can set a flag causing the menu to display even when filtered

Detail By Peter Wooster

User Access Manager

With the “User Access Manager”-plugin you can manage the access to your posts, pages and files. You only create a user group, put registered users to this and set up the rights for this group. From now on the post/page is only accessible and writable for the specified group. This plugin is useful if you need a member area or a private section at your blog or you want that other people can write at your blog but not everywhere.

Detail By Alexander Schneider

Microthemer – WordPress Visual Design Plugin

Microthemer is a visual design plugin that gives non-technical WordPress users a way to customize the appearance of their WordPress theme. Microthemer is intended for WordPress users who demand near full design control but don’t necessarily have any knowledge of CSS .

Live preview | Detail

Further Readings

WordPress: Roles and Capabilities: WordPress explanation on how blog owner can control the ability of assigning roles to a user.
WordPress: Author Templates: This article explains how to change what happens when the blog viewer is visiting one of your site’s author pages.
Creating an “About this Author” for Multiple Authors: How to insert About this Author at the end of every blog post.

Shortcodes were introduced in WordPress 2.5, and allowed the Gallery feature allows the option to add an image gallery to a Post or Page on your WordPress blog. but now you can us shortcode for your theme by using WordPress plugins and can create your own function to display requires result. I was working on my client web site and was required to display one category post on a specific page, I tried few plugins but did not get the proper result so one of blog fellow have given a solution on Simple Recent Posts Shortcodes for WordPress, which help me a lot and here is my code for The Corporation WordPress Theme:

<?php
function my_recent_posts_shortcode($atts){

global $post;

$myposts = get_posts(“showposts=5&category=32″);
foreach($myposts as $post) : setup_postdata($post); ?>

<img width=”120″ height=”120″ <?php the_post_thumbnail(); ?>
<div class=”latest_news_box”>
<h3><a href=”<?php the_permalink() ?>” rel=”bookmark”><?php the_title(); ?></a></h3>
<p><?php the_content_limit(520); ?></p>
</div>
<?php
endforeach;
}
?>

There are different requirement to display content on your blog, Kevin Chard have wriiten lot of usage of shortcode on his blog. You see shorcode usage on the following link: wpsnipp/shortcode. and  Filip Stefansson, the Founder and editor of WP-Snippets, explained in detail about shortcode usage on this link: Getting Started with WordPress Shortcodes (+Examples).

WordPress Plugins for Shortcode

Slider gallery shortcode

This plugin creates a new shortcode for WordPress. With this new shortcode, you can create a slider gallery in seconds just by typing while you’re writing your post or page. The slider will display the images that you have uploaded to the current post or page.

If you need more options, this simple shortcode features multiple attributes that you can set. You can:

• add controls to go back and forward through each slide
• select an specific transition between images (fade, zoom, scroll, curtains, grow, toss and many more)
• show the image title
• set the size of the images displayed in the slider
• wrap the image with a link to the image file
• adjust the transition speed
• set the pause between transitions
• set the initial delay before the first transition
• exclude some selected images.

TitanEditor – The Shortcode Editor On Steroids

Features

• Drag and drop Functionality – Drag, drop, move or delete your short-codes until your satisfied.
• Page template Manager – No more messing around inside your default pages and posts, create your own page templates filled with short-codes.
• Button shortcode editor – Create as many button styles and shapes you want.
• Most common shortcodes included – Buttons, tabs, accordion, toggle, slider, images, columns, lists, message boxes, video, quotes, separator, blog elements, galleria and pre/code
• Quick fill – After adding your columns your able to fill them all by just one click.
• TitanEditor Page Attributes – After creating your page template and you’ve filled and rearranged all components then just create a new page and select your page template from the TitanEditor Page Attributes window and your done.
• Clever editing – Not happy after seeing your freshly baked page, then just select the template through TitanEditor and edit it, TitanEditor remembers where you have left and opens the page just as you left it.
• Screencasts Included – Watch the videos for full instructions on how to use the editor, once your used to it you never return to the wp-editor ever again.
• Blog Post compatible – Your also able to create a nice looking blog post that looks different then any other blog post. Just create a page template ad your content through the editor and assign this page template to that blog post.
• Editors Option Panel – A option panel from where you can enable or diasble the stylings, so if you want to use your own then you only need to disable it.

Tabbed Content Shortcode

A clean, easy to integrate, reusable tabbed content area for your WordPress themes!

Features

• Reusable , add as many as you want on the page!
• Easy to use, activate and copy-paste the sample shortcodes to begin
• Auto sizing on a tab by tab basis
• Help and information admin page
• Easy to integrate into any design

SWS: Nivo add-on for Styles With Shortcodes

Styles with Shortcodes is a great plugin that makes life easier using WordPress whether you are a seasoned developer, designer or just a normal user!

Live preview | Detail

Shortcodes Ultimate

With this plugin you can easily create buttons, boxes, different sliders and much, much more. Turn your free theme to premiun in just a few clicks. Using Shortcodes Ultimate you can quickly and easily retrieve many premium themes features and display it on your site. See screenshots for more information.

Detail

Display Posts Shortcode

The Display Posts Shortcode was written to allow users to easily display listings of posts without knowing PHP or editing template files.

Detail

Category Post Shortcode

This plugin allow you to display post list in your page or post by using shortcode.

Detail

List category posts

The shortcode accepts a category name or id, the order in which you want the posts to display, and the number of posts to display. You can also display the post author, date, excerpt, custom field values, even the content! The [catlist] shortcode can be used as many times as needed with different arguments on each post/page.

Detail

Category Shortcode

This plugin creates the [Category]] Shortcode. The code takes 5 arguments:
number: the number of posts to display. 0 equals the default number. -1 equals the total available.

Detail

Available shortcodes for WordPress Hosted Blog

Miscellaneous | Video | Images and Documents | Audio

Detail

In case, you are using WordPress for your client or have made lots of customizations on core WordPress files, then might not want this message to displayed, because it will overwrite all the files and client site will lost all the changes.

So there are few option to hide it from dashboard through some function adding in function.php file, by using  WordPress plugin to hide this message and manually removing the code from WordPress core file. Different bloggers had provided the solution on their bog like like as follow:

1. Just Open functions.php file from wordpres theme and put following code in that file: (from wordpressapi)

add_action('admin_menu','hide_update_message');
function hide_update_message()
{
remove_action( 'admin_notices', 'update_nag', 3 );
remove_filter( 'update_footer', 'core_update_footer' );
}

2. All you have to do is simply open the theme’s functions.php file and add this: (wpbeginner)

add_action('admin_menu','wphidenag');
function wphidenag() {
remove_action( 'admin_notices', 'update_nag', 3 );
}

3. To get rid of the “Please update now” message in your WordPress dashboard, simply paste the following code on your functions.php file. (wprecipes)

if ( !current_user_can( 'edit_users' ) ) {
  add_action( 'init', create_function( '$a', "remove_action( 'init', 'wp_version_check' );" ), 2 );
  add_filter( 'pre_option_update_core', create_function( '$a', "return null;" ) );
}

4. You can optionally put this code with a condition so that the update message will only be shown to the site admin or other user roles depending of the if-statement in the code snippet below. (fredrikmalmgren)

function hideUpdateNag() {
    remove_action( 'admin_notices', 'update_nag', 3 );
}
if ( !current_user_can('activate_plugins') ) {
    add_action('admin_menu','hideUpdateNag');
}

5. Removing the update message is very straightforward to do – simply add the following lines of code to your functions.php file:(vooshthemes)

remove_action('wp_version_check', 'wp_version_check');
remove_action('admin_init', '_maybe_update_core');
add_filter('pre_transient_update_core', create_function( '$a', "return null;"));

All the above almost do the same thing, If still not satisfied requirments you can use WordPress Plugin to hide “WordPress Upgrade Message” from users and clients dashboard.

Hide Update Reminder

This plugin allows you to hide the update WordPress reminder from all users that are not assumed Administrators (cannot upgrade plugins).

If you have multiple users then this means those who are not admins don’t need to see the message. Useful for CMS based sites, so the client doesn’t see the notice.

Detail

If you want to display notifications to your user when you update something or when you wish to make an announcement. The plugin
“WP update notifier“ is simple yet effective and extremely usefull.

Disable WordPress Core Update

Completely disables the core update checking system in WordPress. The plugin prevents WordPress from checking for updates, and prevents any notifications from being displayed in the admin area. Ideal for administrators of multiple WordPress installations.

Detail

If you are new to WordPress Multisite or have been using it for years,  these WordPress plugins are best for the latest version of WordPress 3.2. They help you to manage your sites on your network easily. You can tweak your CMS specially can maintain and manage its privacy.

Moderate New Blogs

If you are running MultiSite network and after registration new blogs  will wait for moderation. No registrations slip through without your approval. New blogs(aka sites) await a final click from a Super Admin to activate. Keep blog registration enabled and open, keep Super Admin email notices enabled.

Download

Toggle Meta Boxes

This plugin will not hide meta boxes added, this plugin toggles meta boxes for all users and all blogs regardless of Cap/Role (only SuperAdmin can override the limits of the plugin however).
WP3 multisite mu-plugin. Go to Site Admin–>Options to “Enable Administration Meta Boxes”. Meta boxes (post, page, and link edit forms, and dashboard) are unchecked and disabled by default. Extra options to toggle the Quick Edit buttons, Media buttons, Screen Options and Help links.

Download

Menus

Enable or disable WP3 Multisite Backend Menus. Adds options to toggle administration menus at Super Admin->Optons page under “Menu Settings”. WP3 already toggles the Plugins menu, I’ve added a bunch more in the same/similar way.

Download

Multisite Switcher

This plugin adds a simple dropdown menu in administration header that allows you (and every site users) to switch between administration of every site they are member of (and so work for super-admin, admin, contributors,…).

Download

Proper Network Activation

Some plugins have an install procedure that is meant to be run only on activation. However, when you do a network activation, that install procedure is only run for the current site. So, you end up with plugins not working properly on all the other sites.

What this plugin does:

• when doing a network de/activation, it triggers the de/activation hook on all sites in the network
• when creating a new site, it triggers the activation hook for all active network plugins on that site

Download

Multisite User Management

Running a WordPress network? You no longer need to manually add new users to each of your sites.

With this plugin, users are assigned a default role for each of your sites. You determine the default role for each site under the Multisite User Management section of the Network Admin | Settings page.

You can assign different roles for each site or keep a site private by assigning no role.

Download

More Privacy Options

Adds three more levels of privacy to the Options–Privacy page.

1. Blog visible to any logged in community member – “Network Users Only”.
2. Blog visible only to registered users of blog – “Blog Members Only”.
3. Blog visible only to administrators – “Admins Only”.

Mulitsite SuperAdmin can set an override on blog privacy at “Network Privacy Selector” on SuperAdmin-Options page

Multisite SuperAdmin can set privacy options at SuperAdmin-Sites-Edit under “Misc Site Options” as well.

Download

Exclude Plugins

This plugin will allow you to selectively show or hide certain plugins from the normal WordPress user in Multisite, as opposed to showing or hiding all plugins at once.

Download

Activate Update Services

For some reason WordPress removes the Update Services ability (under Settings – Writing) when you create a Multisite network. Activate this plugin to get it back.

Download

WP Multi Network

Turn your multi-site installation of WordPress into many multi-site networks, all surrounding one central user base.

WP Multi Network allows cape wearing super admins to create new network collections of sites, allowing for infinitely extensible site, network, and domain arrangements.

Download

WP Multi Network

Turn your multi-site installation of WordPress into many multi-site networks, all surrounding one central user base.

WP Multi Network allows cape wearing super admins to create new network collections of sites, allowing for infinitely extensible site, network, and domain arrangements.

Download

Enable Multi-Site

This plugin takes care of most of the dirty work of installing Multi-Site on WordPress 3.0. However, there may be some server-side changes you may need to do before upgrading to Multi-Site. Please refer to Plugin Documentationor the WordPress Codex before using this plugin. This plugin only takes care of steps 3 – 5, which will cover most people.

Download

Blue Network Plugins

WordPress 3.0 is cool like Thelonius Monk, but for super administrators coming from WordPress MU, if you head on over to the plugins page, you’ll notice something missing.

Network (or sitewide) plugins are now merged into the entire plugins list!

Download

Other Useful Resources:
WordPress Premium Content
Professional domain mapping
How to Get Posts from all Blogs in Multi Site Network

WordPress Membership Lite

Anti-Splog

The ultimate plugin and service to stop and kill splogs in WordPress Multisite and BuddyPress.

Wiki Lite

Advanced Theme Switcher

When it comes to create or Convert WordPress into multiple WordPress sites, Look at this tutorial “How to enable Multi Site feature in WordPress 3.0?“, which tell you how to set up everything. Here is an other tutorial which tell you what you need to do to activate the multi-site ability and get through the set up and domain mapping process “How to do domain mapping in wordpress multiste network“. There is one Plugin on WordPress directory Plugin Commander, by using this Plugin you can manage all WordPress Multi Site Network Plugins at one place.

Creating New Network Sites:

After converting your site into Multi Sites Network, Follow these steps to add new sites to your network.

1. Go to Super Admin  by Click on “Network Admin” at the Top right of your WordPress Admin area.

2. You are now in the Networking admin Dashboard, and Click on Create a New Site.

3. Fill out all required field for your new blog, e.g. the Site Address field, a Site Title, and Admin Email. Click Add Site to finish the creation. Now you can see the new site added under Network Sites link.  You can visit new site by Clicking “Visit” link on  your new site.

4. You can edit to change the setting for your new site by Clicking on “Edit” link. Aloso you can see User for this site and are able to edit them.

Plugins on Your Multi Sites Network:

I already have explain “How to Manage Plugins in WordPress Multi Site Network” , but there is one more excellent Free WordPress Plugin Service “ManageWP“, You can manage multiple WordPress sites by using this free service and for Self hosted WordPress this would be available soon , there’s a detail article on that Plugin on WPMU “Manage Multiple WordPress Sites from One Centralized Dashboard“, You can read all features of this service by visiting the above link.

Themes on Your Multi Site Network:

Install theme normally as you do on Single WordPress site. Its up to Super Admin to give permission for the usage of particular theme. Under Network Admin click on Themes and check Network Enable or Disable link for the themes you want to be available to the network site:

Best BuddyPress Themes for Social Networking

DynamiX – Premium WordPress Theme
ReviewIt – Review & Community WordPress Theme
LetterPress – WordPress Theme with CMS Features
LetterPress – WordPress Theme with CMS Features
Wordshaft WordPress Theme
Digitalis – Business and Portfolio WordPress Theme

Control User Registration Across the Network:

Go to Network Admin >> Click on “Site” link and Click Edit under the site for which you want to allow people can set up their own sites. Enter value 1 under “Users Can Register” field:

People can sign-up now by visiting /wp-signup.php on your site. There is an easy to provide this link is by adding it to a menu:

That’s all. The site creation link will be available to people and they can add their email and can choose their own sub-domain.They are now ready to run a new blog by login and start blogging with all the normal WordPress features. However, you can allow or disallow plugins and themes for each subsite through the SuperAdmin.

Would you like 100s more of these WordPress tutorials – the same used by Apple, Sun and IBM to learn WordPress?

Every day, people are building great websites with WordPress.
With Open Source Training, they have access to online classes and support from the best teachers in the WordPress world.

Our professional teachers have created videos and tutorials for you that walk you step-by-step through everything you’ll need to build wonderful WordPress websites. These are the same lessons we use to help clients like Apple, Sun, IBM, Hewlett-Packard and NASA.

What’s Included In Your WordPress Training?

	Your WordPress Subscription
Same-Day Support	Unlimited WordPress questions, all answered within 24 hours.
Beginner-level Class	Hours of video tutorials introducing you to all the key WordPress concepts.
New tutorials every week	New weekly step-by-step tutorials on topics suggested by members.
Intermediate-level Class	Take your WordPress site to the next level with multisites, e-commerce, social networking and more.

Open Source Training teaches people how to use Joomla, Drupal and WordPress.

define(‘WP_ALLOW_MULTISITE’, true);

Find more detail on “ How to enable Multi Site feature in WordPress 3.0“. After doing this you are able to access the network page from Tools » Network. By default, you are allowe to run other blogs as a subdomain. You can use other domains for blogs by using  a Domain Mapping plugin (Detail: How to do Domain Mapping in WordPress Multiste Network).

After converting your WordPress single installation into Multi Site Network,  you can do some cool things with it. I will see how to get posts from all blogs in the network.

What if you want to get some recent posts from last updated blogs, not only one blog? Then get_last_updated() is the function that will save your life!

See a simple example that shows last post from last updated blogs:

$blogs = get_last_updated();
echo '
<h1>Last posts in network</h1>
';
foreach ($blogs AS $blog) {
	echo "
<h2>".$blog["domain"].$blog["path"]."</h2>
";
	switch_to_blog($blog["blog_id"]);
		$lastposts = get_posts('numberposts=1');
		foreach($lastposts as $post) :
			setup_postdata($post);
			the_title();
		endforeach;
	restore_current_blog();
}

(Source: wordpress-multisite-blogs)

Reference:

You can read more about WordPress Multi Site Network:

Protect Your WordPress Multisite Network From Shutdown With Anti-Splog and Post Monitoring
How to Get More From WordPress With Multisite Blogs (Network Install)
Best BuddyPress Themes for Social Networking
How to manage plugins in WordPress MultiSite Network
WPMU Functions/get last updated
http://codex.wordpress.org/Category:WPMU_Functions
http://codex.wordpress.org/Function_Reference#Multisite_functions

These are WordPress Themes, which you can use for your Multi Site Network, because they support BuddyPress and BBPress.

ReviewIt – Community WordPress Theme

ReviewIt provides you with a powerful review and community theme, that is also 100% BuddyPress compatible!
Key Features

• 2 Unique Skins – Dark and Light
• Custom Post Types – Reviews and Slides
• Powerful Review System – Utilizes GD Star Rating WordPress plugin (requires PHP 5 )
• Easily Change Tags – Switch the site from movies to games, apps or whatever you want
• Multiple Review Displays – Display reviews in lists, by score, date, based on similarity to other reviews etc.
• Total BuddyPress Support – This theme supports BuddyPress but works just fine without it

Live Preview | Detail

DynamiX – Premium WordPress Theme

Theme features:

• Dual Skin Mode
  – Inner (Main body content) & Outer (Header / Footer area) Skin can be selected
  – Select Skins for entire website and per page
  – Select from 20 Outer Skins and 2 Inner Skins
• Non-Post Gallery Slide Manager (Manage all your Gallery Images/Videos in one area)
• BuddyPress Theme (BBPress Support)

Live Preview | More Detail

TheAllure – Elegant Corporate and Portfolio Theme

TheAllure is a professional and very flexible wordpress theme packed with amazing functionality and a very impressive Design. The Theme has Unlimited color choices. It is packed with lots of shortcodes and a powerful admin panel (PowerPanel) that lets you control every aspect of your website.
The Allure theme is very easy to set up no matter if you are a wordpress beginner or a wordpress pro.
It is also compatible with wordpress MU (Multisite/wp_mu). It is WPML Translation ready and for your convenience, already includes 19 languages for the frontend.
Key Features

• Advanced Admin Panel packed with Options with over 20 sections to help you control every aspect of your website (SelectedTheme’s PowerPanel)
• Unlimited Colors
• WPML and Translation Ready
• 19 Languages Available
• Cufon Font Replacement with over 25 fonts
• Custom Post Types: Portfolio Items, Slider Items
• Supports Custom Menus
• 3 Sliders: Nivo Slider, Thumbnail Slider, Full Content Slider
• Fully Flexible Homepage Layout
• 50+ shortcodes
• WordPress Multisite (WordPress_MU) Support

Live Preview | More Detail

Following are the WordPress Plugins which will allow you to share your blog post on Social Networking sites and you can sell your premium content to your blog users:
SocialPress
Sociology for WordPress: Twitter/Facebook Poster
WordPress Premium Content

Running multiple sites within WordPress, First of all you have to enable Multi Site feature in WordPress 3.0. There are two plugins (Professional Domain Mapping and WordPress MU Domain Mapping ) which will help you to do that. Professional Domain Mapping includeda sixteen page ebook with full documentation and screenshots to help you set up whatever kind of server you have.

WordPress MU Domain Mapping Plugin

This plugin allows users of a WordPress MU site or WordPress 3.0 network to map their blog/site to another domain.

1. Install the plugin in the usual way into the regular WordPress plugins folder. Network activate the plugin.
2. Move sunrise.php into wp-content/. If there is a sunrise.php there already, you’ll just have to merge them as best you can.
3. Edit wp-config.php and uncomment or add the SUNRISE definition line. If it does not exist please ensure it’s on the line above the last “require_once” command. define( 'SUNRISE', 'on' );
4. As a “super admin”, visit Super Admin->Domain Mapping to create the domain mapping database table and set the server IP address or a domain to point CNAME records at.
5. Make sure the default Apache virtual host points at your WordPress MU site or WordPress 3.0 network so it will handle unknown domains correctly. On some hosts you may be required to get a dedicated IP address. A quick check: in a web broswer, type in the IP address of your install. If you are using CPanel, use the Park a Domain menu to set the mapped domain to your main installtion.
6. Do not define COOKIE_DOMAIN in your wp-config.php as it conflicts with logins on your mapped domains.

Illustrated installation instructions can be found here but you can ignore the instructions to place domain_mapping.php in mu-plugins. Thanks Otto.

Configuration

On Super Admin->Domain Mapping you can configure the following settings:

1. “Remote Login” can be disabled. Useful if you’re hosting totally separate websites.
2. “Permanent redirect” uses a 301 redirect rather than 302 to send visitors to your domain mapped site.
3. “User domain mapping page” allows you to disable Settings->Domain Mapping that the user uses.
4. “Redirect administration pages to network’s original domain (remote login disabled if this redirect is disabled)” – with this checked, if a user visits their dashboard on a mapped domain it will redirect to the dashboard on the non mapped domain. If you don’t want this, remote login will be disabled for security reasons.
5. “Disable primary domain check. Sites will not redirect to one domain name. May cause duplicate content issues.” – ignore the primary domain setting on your sites. The same content will be available on multiple domains and may cause problems with Google because of duplicate content issues.

Super Admin->Domains allows you to edit the domains mapped to any sites on your network.

For Cpanel users

If your domain uses the nameservers on your hosting account you should follow these instructions. If the nameservers are elsewhere change the A record or CNAME as documented above. Add a wildcard subdomain/virtual host record to your site’s DNS record in Web Host Manager (WHM). If you do not have access to WHM, you must email your web host and ask them to make this one change for you. Should be no problem:

• Go to “Edit DNS Zone” and select the domain of your WPMU installation and click “Edit”.
• Below “Add New Entries Below This Line”, enter in the first box (Domain) an asterisk: “*”.
• The second box, TTL, should be “14400″.
• The third box should be “IN”.
• Select A Record Type from the drop down “A”.
• And in the last box, paste in the IP address of your website/network.

From Cpanel, click on the “Parked Domains” under the “Domains” section:

• Under “Create a New Parked Domain” enter the domain name you want to add to your network.
• Click the “Add Domain” button.
• It should add the domain to the list of parked domains and under “Redirect to” it will say “not redirected”. That is OKAY.

Now you’re ready to do your domain mapping.

Download WordPress Domain Mapping

Professional Domain Mapping Plugin

Professional Domain Mapping is the ideal plugin to use if you wish to hide the originating domain of the network, and where you wish for the Super Admin to be the only one with access to the menu. You can also add additional aliases.

• Less menu option, less confusion over settings.
• Hides original subdomain
• Specific instructions and screenshots for common hosts.
• We’ll also support the free domain mapping plugin!

$29.95 includes the plugin, the 16 page ebook and support! Now updated for 3.1 and includes specific instructions for hosts like WPWebHost , Hostgator, BlueHost, Hostmonster and more .

Purchase Professional Domain Mapping

Note: If you require separate domains in your installation with the ability to have member sites associated with those domains (child blogs), then we suggest the Networks Plus plugin instead.

Useful Resources:

WordPress Premium Content

User Locations
Question & Answers – Green Automatic
What is domain mapping?
WordPress 3.0: Multisite Domain Mapping Tutorial
Best BuddyPress Themes for Social Networking
How to manage plugins in WordPress MultiSite Network
How to enable Multi Site feature in WordPress 3.0?

MultiSite functionality is not enabled by default in WordPress 3.0, You need to check out the new MultiSite settings in the WP Admin under Tools > Network. To enable MultiSite, you need to add the following line of code in  wp-config.php file:

define(‘WP_ALLOW_MULTISITE’, true);

A new link “Create a Network” will appear in the WP Admin under the Tools menu, After uploading your updated config.php file to the server, where you will define a few options and create a network.

Clicking on the Network link in the Tools menu loads the network setup/installation page. It should look like this:

After adding required information in “Create a Network”, install and update your wp-config.php file and .htaccess. Before updating never forget to backup your both file.
Now you will see a New feature in admin panel as “Super Admin” in Dashboard.

Welcome, Super Admin!

You are now “Super Admin,” and have ultimate control over every site in your network. Here you can mange Create New Site, Create New User along with other options. The good news is that all of your network settings are available through the Super Admin menu panel located at the top of the left sidebar.

Enable Multisite in WordPress 3.0 With One Click!

Easily upgrade your WordPress 3.0 blog into Multi-Site with the click of a single button.
This plugin takes care of most of the dirty work of installing Multi-Site on WordPress 3.0. However, there may be some server-side changes you may need to do before upgrading to Multi-Site. Please refer to Plugin Documentation or the WordPress Codex before using this plugin.

Download | Detail

WordPress 3 MultiSite Setup:

More Resource:
Common WordPress Multisite Problems and Solutions
Enable Multisite in WordPress 3.0 With One Click.
How to enable Multi-Site option in WordPress 3.0
How to Enable WordPress 3.0 Multi-Site