2015 Update: While still functional, you’re much better off using Snow Leopard as your daily driver OS. It’s received several more years of security updates and application support.
It’s finally out. After a year of being down, I can rerelease it. iTunes works (although only with iOS 4.2.x and below devices) in this release, and it no longer has my address and phone number stored in Address Book. It also is about 2GB smaller of a download. I cannot recommend you use this as your only OS due to the fact it’s a year and half old beta of Lion (some software support issues) but it certainly is worth installing to check out the new Mail.app, Mission Control, LaunchPad, Full screen apps, and more. Unfortunately, this predates iCloud, so it does not give you those online syncing features with iPhoto. Right after compiling RoaringCoreB2 I actually found RoaringCoreB1 on my friends HDD that had been lost. Still, it’s worth not giving away where I live.
@chic_tyler on twitter.
Video Guide from a user: