Pod2g has announced via Twitter that he successfully made untethered jailbreak of the on iOS 5.1. Previously, three parties had demonstrated the jailbreak of iOS 5.1: I0n1c, the iPhone Dev-Team, and Chpwn/Phoenixdev. Only I0n1c claimed untethered jailbreak, but made it clear that he will not be releasing his jailbreak to the public.
Thankfully pod2g has announced that he’s also succeeded in untethering the jailbreak.