Great news, I0n1c has just announced the successful jailbreak of iOS 5.1 on the iPad 2 via a series of pictures posted to his Twitter. We hope this jailbreak still can work on the new iPad as he promised before.
I0n1c is the hacker behind the 4.3.1 untethered jailbreak. While no further information has been provided on his exploit, we are hopeful that this is an untethered jailbreak that would work for all devices on iOS 5.1, including the iPhone 4S; however, we cannot confirm that yet.
If the exploit is in the OS it could even work for the iPad 3 scheduled for release tomorrow, as I0n1ic hints, "Anyway so maybe the iPad 3 will not be jailbroken tomorrow, but on Monday or whenever I get my iPad 3."