Things have progressed to the point where we don't expect anymore roadblocks. ETA for greenpois0n is 10/10/10 at 10:10:10AM
The jailbreak is based on the SHAtter exploit found by pod2g. It will likely be released at http://greenpois0n.com/ and will include the ability to hacktivate.
We will be posting tutorials on how to jailbreak your specific device as soon as the jailbreak is available. Remember there is no unlock yet for iOS 4.1, so if needed, be sure to follow our instructions to insure you remain unlocked.
Chpwn: Please remember that SHAtter and greenpoison are /only/ possible on the fourth-gen devices: iPad, iPhone 4, and iPod touch 4G.
MuscleNerd: the ultrasn0w carrier unlock won't work on 4.1's baseband (and you can't go back to earlier basebands)
MuscleNerd: SHAtter doesn't apply to iPhone3GS (or iPod touch 3G). New owners of those should wait for future @comex JB