MuscleNerd, a member of the iPhone Dev-Team, has announced that the SHAtter jailbreak itself is tethered but comex has come up with a way to untether it!
Those reading between the lines: Yes SHAtter itself is tethered. @comex came up with a way to untether it on 4.1/3.2.2
SHAtter is yet another breed of exploit. Bootrom-based but requires userland 'assistance' for untethered boots (@comex did this for 4.1)
This is excellent news since a tethered jailbreak would require your iDevice to be connected to the computer for reboot.
The Greenp0ison jailbreak will be released October 10th at 10:10:10 GMT.