To answer everyones questions:
It is not tethered, but only for 4.1 as they will patch comex's exploit in the next patch...
yes it can work for 4g as thats what i used on my ipod touch 4g...
for the 2g, sorry but to update your 2g to 4.X and then try to jailbreak there will make you lag so bad... i would look around for something for 2g (googles your friend =D ) but i think they are all currently tethered