iPhones have been unlocked now, so you can use them on Verizon (the only other GSM carrier in the US) and in Canada, I know Rogers (but data plans are amazingly over-priced) you could use one and I'm unsure about the other carriers.
since iphone and ipod touch run the same binary and code, im sure as soon as the ipod touch is released, it will be hacked to the point where it runs all iphone apps (they will probably find a hack for the phone and camera app too :razz
Bleh, I meant T-Mobile, I got my providers messed up.
I dunno, an iPod touch is nice, but I have 10 GB of music, I don't wanna be ****ing around with videos. I'll wait until a larger one comes out, atleast 32 or 64 GB before I get one.