No, no, the world's not ending and I'm not announcing an epic prank. Yellowsn0w is a SIM un-locker for the iPhone 3G. The name might change before release, and I kinda hope it does. MuscleNerd from The iPhone Dev Team has uploaded video proof of the hack. Even when run manually, as seen in the vid, it's quick and easy. As the narrator says, the package will be released on the 31st. Looks like an unbelievably simple download and tap. iEnvy.