WordPress "Must-Use" Tutorials
WordPress multisite how to - making sense of the network feature from what was wordpress mu
Donncha wrote here about the new MU he just released. You can read all about what he has to say, but the biggest and most noticeable to me was a bump in the version numbers. There’s also a nonce on signup to help defeat splogs and post revisioning. Bunch of goodies rolled in from regular WordPress.
Go download it from his entry and test it out. 
Includes 3 ebooks with plugins -
Network Home Pages: aggregate global content, set up sitewide tags, create a huge tags cloud like the one seen on WordPress.com, global footers and menus, setting defaults & more
Custom Registration: sign up on sub sites, multilingual signup pages, stop spam blogs
WP Curator: pick and choose posts from sub sites to feature on the main home page of your network
Network Home Pages, Custom Registration & WP Curator – $35.90 for all three. Purchase
Scary…scary to have to upgrade and hope I don’t miss something;)
Funny. I can’t find any upgrade instructions…