Our iPhones come unlocked out of the box down here in NZ so when I head off to the US for a month tomorrow I plan on picking up a prepay SIM in the US so I can use my iPhone without worrying about the *huge* roaming costs I could otherwise expect. Can anyone recommend the best value prepay plan. Will use a small amount of voice / SMS daily but I'm most interested in data. I've got a 3G. Not sure how much this affects thing but I'll be travelling to SFO, BOS, DCA and NYC. Cheers!