According to Dev Team member MuscleNerd, the current version of Redsn0w can still jailbreak the beta of iOS 5.01. In case you missed the news, Apple released a beta of iOS 5.01 to developers yesterday to address various bug fixes; notably battery life. The good news is that you can still jailbreak it using Redsn0w. If you have decided that you can’t suffer the iOS 5 bugs any longer but don’t want to forfeit your jailbreak either, you are safe to proceed.
Devs trying today's 5.0.1 beta can JB with existing redsn0w (but select the 5.0 IPSW thru GUI or command line)
The jailbreak remains a tethered solution for now and does not work with the iPhone 4S or the iPad 2.
Update: Redsn0w has now been updated to version 0.9.9b8 and it now supports iOS beta 5.0.1. There is no need to use the iOS 5.0 IPSW anymore!