Why use an inferior Wordpress Google Maps plug-in when your theme can be the map itself…? The WPMU gMaps theme is truly unique, in that each page is a full-screen Google map with fully interactive overlays!  Specifically built for Wordpress MU, the theme provides out of the box functionality for aggregated Network statistics and sign-up processes, but can also be used on standard Wordpress installs.

AJAX technologies provide fancy tabulated info windows for posts with fully styled custom-built drag and drop web-top powered windows floating above an unlimited number of geoRSS-fed pages, you can display up-to customisable markers on your homepage or an unlimited number via an integrated auto-generating geoRSS feed.

For those wishing they could go back to an older version of the MU default theme, or see other important changes, the Wordpress MU Trac system keeps track of all the previous releases of Wordpress MU.

The WPMU Farm Spectagular Pack contains a whopping 94 themes, many with customizable headers, all fixed up to work with MU (i.e. not an ounce of user code required) and best of all - completely set up for tags and so 100% WPMU 1.3 / WP 2.3.1 compatible. Not the best of themes, but all free and all ready to go for those desperate to get started.

Although Tarski was specifically designed for Wordpress, it comes with MU functionality built into it, and as such, makes it one of the cleanest and most elegant free themes available for Wordpress MU.