So far I have info that 3 different jailbreaks exist for iPad 3.
First was MuscleNerd with the root access:
and Cydia installed
Then i0n1c showed video of untethered iPad 3
First was MuscleNerd with the root access:
Shortly after chpwn and phoenixdev showed pictures of a third iPad 3 WIFI jailbreak
So these days are busy days for jailbreakers. iPad 3 was not a big challenge for the jailbreakers which exploited it so fast.
Advice: If you are an iPad 3 owner do not upgrade your firmware in near future, a jailbreak is coming for you!