P0sixninja, a member of the Chronic Dev-Team has been working on GreenPois0n jailbreak for iPhone, iPod Touch and iPad for months now. A few days ago we reported on a new bootrom exploit to jailbreak iPhone 4, 3GS, iPod Touch 4G and iPad found by Pod2g, another Chronic Dev-Team member and now http://greenpois0n.com/ gets an update.
GreenPois0n could not be released because Chronic Dev-Team and iPhone Dev-Team decided to postpone Greenpois0n in favor of JailbreakMe. Now that the time has come, Pod2G has tested and confirms that GreenPois0n works fine to jailbreak iPhone 4 on iOS 4.1. MuscleNerd also reported that iPod Touch 4G and iPad are also vulnerable to the exploit.