Boy, that was quick! Within 24 hours of the release of iOS 5.1 the hacking community has already released a jailbreak for the OS. It is an not an untethered jailbreak though, which means you would have to connect your device to a computer while rebooting. The updated jailbreak by Redsn0w now stands at version 0.9.10b6. At the moment, the jailbreak does not support A5 chip devices which include iPhone 4S and iPad 2 and also A5X device which is the new iPad 3. Detailed instructions and download links available here.