GreenPois0n which is an infamous jailbreak of anything and everything Apple, though right now there is a challenge of whether devices running iOS 4.1 can actually be jailbreak, well GreePois0n is allegedly coming out with an "ultimate" jailbreak tool that will jailbreak not only the iPhone 4 but every other iOS 4 device, the problem is there is no release date but as the old saying goes " You can't rush perfection" so maybe the unannounced release date is actually a good thing. The tool is going to be a low level version of the popular SHAtter exploit.
In related news a hacker from the iPhone Dev Team who goes by the alias of "p0sixninja" has confirmed a work around so that jailbreak iPhone 4's can bypass the activation phase of iTunes. It has also been reported that the people who are on the 05.14.02 baseband won't be able to jailbreak until the new version of Ultrasn0w is released.
The challenge of tackling the iOS 4 jailbreak may seem like a long and endless fight but now there is a light at the end of the tunnel and maybe we can expect these to release sooner than expected, let's keep our hopes up and keep our eyes open for any new updates.
Source: Redmond Pie