There will be no untethered jailbreak for iOS 4.3.4
Famous iPhone hacker Stefan Esser, also known as i0n1c, recently wrote on twitter that we should not expect untether jailbreak for iOS 4.3.4 anytime soon. i0n1c was the one who created untether for iOS 4.3.3 firmware.
Our advice is simple - save your 4.3.3 SHSH keys asap. With these SHSH keys you will be able to restore to iOS 4.3.3 anytime, without - only iOS 4.3.4. Here are tutorials for you.