hazardcell

A newer version for WP3.0 is in the works. I would have loved to release it on time for the release of 3.0 but I’m having my finals at the moment so it will have to wait until June 2010. Will include single sign-on as well.
This plugin is for WordPress MU
This plugin basically allows you to host blogs on multiple domain names while maintaining one main site.
For example, the main site could be example.com but users will also be able to sign up for blogs on example.net, example.org or any other domain name that you choose to add.
<ul>
<li>All the sites will have the same settings</li>
<li>No extra blogs/tables are created for the additional domain names</li>
<li>All blogs will be viewable on the Site Admin blog list</li>
</ul>
Alternatively, if you would like to request a feature and/or report a bug, please visit the <a href="https://wordpress.org/tags/yet-another-multi-site-manager" rel="ugc">forum</a> or the <a href="https://plugins.trac.wordpress.org/browser/yet-another-multi-site-manager/" rel="nofollow ugc">trac repository</a>. You will have to login with your WordPress.org username and password to access these.
<h3>Known Issues/Limitations</h3>
<ul>
<li>Remote login does not work with this version</li>
<li>Only tested with VHOST installs in root directory</li>
</ul>

Yet Another Multi-Site Manager

Allows blogs to be created on multiple domain names while maintaining only one main site for all domain names.

jroakes

This plugin will give you the ability to pull up any (non-Super Admin) user and in one click add that user(with a global role) to all sites in your MU install. Likewise, if you want to remove a user from all sites it is one click as well. CAUTION: WordPress has an optional mechanism when deleting a user from a site that will allow you to assign that users posts to another user. I have ignored this for this release. Please take a DB backups until you are used to this plugin and Multi-Site.

Multi-Site User Replicator 3000

WP3.1 multisite "mu-plugin" that allows you to add a user to all sites or no sites. Just drop in mu-plugins.

Yet Another Multi-Site Manager vs Multi-Site User Replicator 3000