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.
The iPhone Dev team has just released the second beta of their untetheredRedSn0wjailbreak (the first beta has been released few hours ago and has more bugs).
New jailbreak is called “Jailbreak Monte”, as it uses new “backup method”. The iPhone Dev Team warns that their beta-version is not a general release and you should back up all your media before using it. There are also other limitations and bugs: