iPhone Dev Team has released and updated version of Redsn0w, Redsn0w 0.9.8b1 to jailbreak iOS 5 beta which was announced at WWDC 2011. The jailbreak tool release is purely for dev users only who want to make their jailbreak apps compatible with iOS 5.
Unfortunately Redsn0w 0.9.8b1 to jailbreak iOS 5 beta is only available for Mac users whereas Windows users will need to wait till final iOS 5 is release on this fall. Also note that iOS 5 beta is only available to developers registered for Apple iOS Dev program.
Here is what iPhone Dev Team says
THIS JAILBREAK IS INTENDED ONLY FOR DEVELOPERS OF JAILBROKEN APPS! There are just too many broken components (Apple’s official apps, 3rd-party App Store apps, Cydia apps, MobileSubstrate apps, etc) for this to be useful to anyone but those truly looking to fix bugs in their iOS 5 jailbroken apps. (Seriously!)
THIS REDSN0W WILL NOT HACTIVATE 5.0b1! You need to be an iOS developer with a registered UDID to get past all the new activation screens. PLEASE DON’T PIRATE APPLE SOFTWARE! Only registered devs with Macs can develop iOS applications, and only those people will have legitimate access to the beta IPSWs.
THIS IS A TETHERED JAILBREAK ONLY! No new exploits are being exposed with this jailbreak (it uses geohot’s limera1n bootrom exploit), but that comes at a cost. You will need to use redsn0w to “Just boot tethered now” to be able to use many things, including Cydia and Safari. If you see a white icon for Cydia, or if Cydia or Safari crash when you open them, it’s because you didn’t boot tethered.
The way redsn0w works, you will very likely be able to use this on upcoming iOS5 betas, just by continuing to point redsn0w at the 5.0b1 IPSW. So keep that IPSW handy!
Redsn0w 0.9.8b1 supports iOS 5 jailbreak on iPhone 4, iPhone 3GS, iPod Touch 4G, 3G & iPad.