1. first you need to add this line to your wp-config.php file:

define(‘WP_ALLOW_MULTISITE’, true);

after that you will see a new option under Tools, it will be called Network.

Now you need to follow the regular WordPress Mu steps and then press the install button.

2. after installation complete you still need to make some changes, add a new folder in the wp-content folder called blogs.dir, it is a folder for all the content and media of the sites in your network.

3. then you need to add some lines to your wp-config again and some lines to your .htaccess. as seen in this screenshot:

4. Now your regular WordPress installation is a Multi sites Network you can use as you used to work with your WordPress Mu. now we just have to wait and see if the upgrade from wordpress mu websites will go smooth as expected.

New Registration Details, No More Admin and generated password

WordPress 3.0 is changing right from the very first stage, installation and registration, no more default admin user name and generated password, now the admin can set is own username and insert the desired password by himself.

New Default Theme – twentyten

finally the default wordpress theme is changing. there are lots of new features in the new default theme called “twentyten” (2010) like Drop Down Page Menus, 6 Widget Areas, Gallery Posts Styling, HTML 5 Validation, Header Image , Background changing support and much more.

Menu Manager

Now you can add menu manager to your theme and let your users create their own menu, not just by pages but also from categories, posts and custom links. excellent feature.

Custom Header Support

WordPress 3.0 supports changes in your header built in without any need of theme options. you can let your theme users upload new header images and use them, they can also choose the colors of the header and many more options.

Custom Background Support

In the new version you will be able to add your own background and change the colors of it. as long as the theme support it.

Network – the WordPress mu part of the story

When WordPress version 3.0 will be released (they talk about may 2010), wordpress mu will cease to exist and the two platform will merge into one will be called – WordPress Multi Site. there suppose to be a script to tranform your WPMu to reular wordpress. more details about this in the near future.

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Download wordpress 3.0 alpha !!! – http://wordpress.org/nightly-builds/wordpress-latest.zip

read about Custom Post Types – http://kovshenin.com/archives/custom-post-types-in-wordpress-3-0/1

more about the new default theme – http://2010dev.wordpress.com/ and here – http://blog.ashfame.com/2010/02/wordpress-3-new-default-theme-twentyten/

more about Background support – http://wpengineer.com/wordpress-3-0-custom-background-support/

First you must remember, not all themes work with WPMU, see WPMU Theme Compatibility.

Theme Category on WPMU.org – http://wpmu.org/category/themes.

All themes some are premium from wpmudev.org – http://wpmudev.org/themes

WPMU Triden

triden

WPMU Dixie

dixi

WPMU Nelo

nelo

Edublogs Theme

edublogs

The Prologue theme – http://mu.bloggles.info/category/wpmu-themes/

Theme packs for your WordPress Mu subscribers

Two great theme packs 86 themes + 30 themes – http://wordpressthemes.pro/wpmu

In case you are working on a traveling website using WPMU here is a great pack for you, 30 New Cool WordPress MU Travel Themes – http://www.wordpresstravelthemes.com/30-new-cool-wordpress-mu-travel-themes

Farms 100 big ones theme pack – http://premium.wpmudev.org/project/farms-100-big-ones-theme-pack-updated

You can upgrade from 2.6.5 quite easily, just:

1) backup eveything

2) delete your WP-admin and WP-includes

3) delete all files in the root directory (I prefare leaving the wp-config, and not delete this file)

4) add these two lines:

define( ‘NONCE_KEY’, ‘HStKtEP!B&KF8RVr!FgrVoMM’ );
define( ‘AUTH_SALT’, ‘sGoBeog@D8KB91I7oeCu&e(&’ );

before:

/* That’s all, stop editing! Happy blogging. */

5) and you’re done.

tell us what you think of the new version.

———-

some more information about WordPress Mu 2.7:

the timeline – http://trac.mu.wordpress.org/timeline

from the blog of Donncha O Caoimh – http://ocaoimh.ie/2009/01/28/wordpress-mu-27/

from the WordPress Mu official forum – http://mu.wordpress.org/forums/topic.php?id=10163

while most of the plugins we are using with a regular blog of wordpress can also be used on a WordPress Mu website, there are a fewer places where you can find plugins for WPMU. here’s a list of the better places to find them. please feel free to add more places on the comments area.

WPMU.org

The plugin category in WPMU.org – http://wpmu.org/category/plugins/

WPMU DEV Premium

By far the largest collection of plugins in one place – http://premium.wpmudev.org/wpmu-plugins/

A List of Plugins for WordPress MU By bavatuesdays

Large and very useful list of plugins for WordPress Mu. – http://bavatuesdays.com/a-list-of-plugins-for-wpmu/

WPMU Tutorials

The plugin category in WPMU Tutorials – http://wpmututorials.com/category/plugins/

WordPress Mu Official Forums

The Plugin Tag In WordPress Mu Official Forums – http://mu.wordpress.org/forums/tags.php?tag=plugin

WordPress MU Plugin

A nice collection of plugins. – http://mu.bloggles.info/

WP Assist

The WordPress Mu category on WP Assist, including some plugins also. http://wpassist.com/category/wordpress-mu/

BuddyPress

One way of using WordPress Mu is installing it and then adding the BuddyPress plugins and themes.

BuddyPress DEV

The only BuddyPress plugins and themes website at the moment – http://buddypressdev.org/plugins/

BuddyPress Forum

The official BuddyPress Forum, I chose the PLUGIN tag for you. – http://buddypress.org/forums/tags.php?tag=plugin