According to the iPhone Dev Team, it has incorporated Pod2g's work in creating the first widely and freely available untethered jailbreak for devices powered by iOS 5.0.1 devices using Apple’s A4 processor.
The jailbreak Redsn0w 0.9.10b1 is compatible with A4 devices including the iPhone 3GS, the iPhone 4, the iPhone4 variant with CDMA, the original iPad 1, the iPod touch 3G and the iPod touch 4G. Unfortunately, jailbreaks are not yet made available for those with iPhone 4S and iPad 2 models, which are powered by Apple’s more powerful A5 processor. Jailbreaking allows end-users to bypass Apple’s security restrictions and gain full access to the underlying operating system, with the freedom to run third-party software not endorsed by Apple.
Redsn0w 9.10b1 was followed by 0.9.10b2 and 0.9.10b3 to fix several issues with the pre-existing iOS 5.0.1 untethered JailBreak. However, users are still reporting various issues. One major concern has been raised by those using the Safari browser. The Safari browser has been found to freeze and hang even after many attempts by users. Users have also complained about the fact that they haven't received any more notifications about the iPhone 4.
These issues are expected to be fixed with the possible release of the next beta version of Redsn0w.