Many iPhone users out there like the handset, but aren’t big fans of being locked to one network or limited to using only approved software. For this type of user jailbreaking, their device is often one of the first things done.
The catch is that with each update the jailbreak crowd has to find another way around the lockdowns Apple puts into effect. With iPhone OS 4.0, coming soon jailbreak artist MuscleNerd is already at work on jailbreaking the new OS.
MuscleNerd has succeeded already with some specific stipulations. First, the jailbreak only works on the iPhone 3G. The second is that the jailbreak software is only for developers. The third caveat is that reports are the jailbreak is unstable now with reports of wireless connectivity issues. Still, this is certainly a start and we can expect things to get better.