if its the 3g im fairly sure you cant . but i haven't been checking the scene recently
if you have the original i no you can . you have to jail break it and then install certain apps that are of questionable legality the information i post here is for information purposes only i don't think you should do this and i take no responsibility and all that crap but jail breaking is your best bet .
the contracts suck balls don't they ?
You need to unlock a mobile to change its carrier.For iPhone I suggest the remote unlocking method would be best suited.To get this service for your iPhone you can approach Unlock-zone.com and easily remove the network lock.