So far, the good people from DEV have stated that this will for now be a tethered jailbreak, meaning if you turn off or restart your idevice you will have to rejailbreak it. So for now don't upgrade to 4.0.2 or 4.1, that is if you still want to keep your jailbroken idevice jailbroken and unlocked. Also upgrading to 4.1 means upgrading the base band, and that is something you can't downgrade = no possible way to carrier unlock. This is what what we have for now, but rest assure there are people trying to find better ways to fight this and make Steve Jobs cry at night.
its like just installing a new os on a computer its not ilegal and apple should know better THERE SLOGAN IS THINK DIFFERENT i dont think that they were thinking at all when they made jailbreaking harder