Despite some good signs on untethered jailbreak for iOS 5, there is no iOS 5 untethered jailbreak as of now. But thanks to a new tweak "SemiTether" at "Cydia" users can now boot their iDevices running jailbroken iOS 5 without needing a computer.
The semi-tethered jailbreak allows users reboot anywhere but with some limited functionality, "SemiTethred" users can use their phone, text, and many other features but will mostly sacrifice the "Cydia" tweaks which require a usual "Just Boot" re-exploit using "redsn0w".