Jailbreak for iOS 5.0.1 beta released
The iPhone Dev-Team has updated RedSn0w with support for jailbreaking iOS 5.0.1 beta which was recently released for iOS developers. (UPDATE: iOS 5.0.1 released)
RedSn0w 0.9.9b8 recognizes 5.0.1 beta and you don't have to "point at 5.0 IPSW" any more. Since the IPSW isn't public, you'll still need to provide it once to redsn0w (Extra -> Select IPSW).
Mac users can also create custom firmware and preserve baseband for unlock. However ultrasn0w doesn't get updated for betas yet.
This is still a tethered jailbreak for all except old-bootrom 3GS users.
You can download RedSn0w from here.
Our step-by-step tutorials are available here.
UPDATE: to jailbreak ioS 5.0.1, just point to iOS 5 IPSW