This news was firstly publicized through Twitter by MuscleNerd displaying Cydia 1.1.5 on the iPad 3 running on iOS 5.1. In case you miss that announcement on the screenshot, therefore I put red arrow pointer on the screenshot to easily see it that says iPad 3, iOS 5.1, Cydia 1.1.5.
This is of course a good news for users who have already bought the 3rd generation of iPad and also motivates people to buy the Apple's latest tablet computer.
However there is no further explanation whether it will be untethered or tethered jailbreak, but of course the notification will be disclosed soon.
Anyway here is the screenshot of the jailbroken iPad 3 on iOS 5.1 with Cydia 1.1.5 running.
And as for ETA or when it reaches a public release, this too there is nothing to tell now. Because MuscleNerd has emphasized that this jailbreak is still in the first step in the process for releasing to the public. Therefore, waiting is what we need to do now until the iPhone dev team finished the entire development process before it goes for public usage!