Enable WordPress 3.0 Multisite the Easy Way
As you may know enabling and setting up the multisite feature on the WordPress 3.0 is not that easy. You can find the instructions on the WordPress.org site.
The good news is that there is now a plugin that simplifies the process significantly. You can find the WordPress Multi-Site Enabler Plugin over on the JG Web Development site.
This plugin only sets the options needed in your WordPress install. It does not do any necessary server configuration. Make sure you check out the system requirements’ information on their site before you use this plugin.