The iPhone Dev-Team recently released RedSn0w 0.9.8b7 which brings explicit support for a tethered 4.3.5 jailbreak as well as new iOS 5.0b6 iPad 1 jailbreak:
Apple updated the iPad1 iOS5b6 IPSW without changing its version number or filename, so we’re releasing redsn0w 0.9.8b7 to handle both the original and changed IPSW. We’ve also added explicit support for a tethered 4.3.5/4.2.10 jailbreak (instead of pointing at the 4.3.4/4.2.9 IPSWs) and fixed a 4.2.10 problem.
We’ve released redsn0w 0.9.8b6 to jailbreak iOS5 beta6 (point it directly at the beta6 IPSW).
Two important notes about this version:
(1) Please let your device boot normally to IOS5b6 and do a clean shutdown (slide to power off) before jailbreaking.
(2) Boot logos have intentionally been disabled for now, so you’ll see a black screen on tethered boots (you can re-enable logos or verbose boot with command-line options if you really want them back).
Due increased sensitivity to abrupt filesystem shutdowns in IOS5b6, it’s very important that you do a clean shutdown before running redsn0w.
MuscleNerd recently Tweeted that iOS 5 beta 1 jailbreak is already available. DevTeam released Redsn0w 0.9.8 b1.
For now the jailbreak is tethered (you have to run redsn0w each time you reboot) and available for Mac OS X only. It will not activate your device, so you need have registered UDID. iPhone 3GS users with 06.15 baseband: redsn0w will get you past the iTunes restore error. This redsn0w will probably work on future versions of iOS 5.