BuddyPress.org

Just do it!

I did it from an installation of WP2.7.1 by using the export/import feature and it worked well.

Dumbass me though forgot to transfer the image folders into the WPmu install so of course I am editing all my posts.

The only problem I found was that my users had to be manually added to mu/bp after the fact, but I did not lose the info in the transfer