Geohot has awoken and returned to jailbreaking it seems. Today the limera1n jailbreak was released for iOS 4.0-4.1+ which is now unpatchable. By unpatchable it means that Apple should not be able to break the jailbreak with an update. The update is also untethered thanks to Comex and his Jailbreakme according to the website. If you rely on a carrier unlock on your jailbreak to not use Limera1n as it will re-lock you phone and it will not be able to be unlocked as it will update your baseband.