I used to write about WordPress Mu (now called multi site) and BuddyPress tips for beginners and intermediate on a different blog, but lately I've redesigned (BuddyPress default theme customized) and restarted updating beneficial information to users.

http://en.wpmubp.org/

Please join Facebook fan page if you are a Facebook user. RSS is available via feedburner. BuddyPress themes are very easy, even a non designer/programmer like me can customize. If you are someone like me, then my new site should help you.