The supposed Gull1hack team released their jailbreak tool, that was, apparently, supposed to jailbreak all Apple touch devices, on OS 3.1.3, on all bootroms. It turns out the whole thing was a fake, according to this message you receive, upon running the program:

Seems it was just some smart ass kid trying to prove a point. This program has nothing to do with jailbreaking any Apple touch device.

So, to repeat, this jailbreak is a fake. DO NOT update to OS 3.1.3 in iTunes, if you don’t have to.