Dave Lester did a fine job of compiling a long list of Universities that are using WPMu in one capacity or another. It’s a great list, and there are at least 40 institutions on there I had no idea about. Add to this list the work Mario Núñez-Molina did last year and add a few additions to his list and you may very well have over 100 institutions using this application. And as the recent comment on his post suggest from the University of Melbourne, there are probably a heck of a lot of international universities that are using this application that we have no idea about.
Now, Mario went above and beyond and made a slide show of screen shots for every install–I do love his fanaticism and I can completely relate He just turned his diigo bookmarks tagged wpmu_university into a slide show, pretty cool.