Sn0wbreeze, a well-known jailbreaking tool for Windows, now has support for iOS 5 Beta, which was jailbroken recently using Redsn0w for Mac.  As of yet, only tethered jailbreak is possible, meaning that you have to connect the device to a computer when powering it on in order to boot it into a jailbroken state. This jailbreak supports the following devices running iOS 5 beta 1: iPhone 3GS iPhone 4 [GSM] iPhone 4 [CDMA] iPod Touch 3G iPod Touch 4 iPad 1G THIS IS INTENDED FOR DEVELOPERS ONLY! SnowBreeze is currently the only jailbreak tool for iOS 5 Beta 1 which is available for Windows users.  This will also preserve your old baseband so that you can unlock your phone in then future using Ultrasn0w.  The current version of Ultrasn0w unlock tool isn’t compatible with iOS 5 Beta 1. Jailbreaking iOS devices is a very controversial subject.