You will find plenty of new qualities in wordpress 3., probably the most important may be the multi-site function, that was implemented in wordpress MU. So, How do i enable multi-site function in wordpress 3.? Will it support stand alone subdomain?

http://codex.wordpress.org/Tools_Network_SubPanel

yes, automatically, it really works much like previously for single sites.

Take a look URL: http://codex.wordpress.org/Create_A_Network

Also note you need to let the variable Wordpress_ALLOW_MULTISITE in wordpress_config.php

define('WP_ALLOW_MULTISITE', true)

right before

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

hope that actually works...

Yeah, the majority of the additional features in Wordpress 3. are difficult to getOrallow. I come up with quick tips on new Wordpress features with code good examples. Hopefully it's useful...