Data-plan for the USA
I'll be living in the US for 6 months soon and I'm looking for a way to use my unlocked iPhone 4 on a pay-as-you-go plan with data. Do you guys know anything good?
You can only use T-Mobile or AT&T. Note that they have different 3G frequencies, and you might have difficulties using 3G on T-Mobile. To the best of my knowledge these are the only GSM networks in the US.
Note that AT&T are very protective of their iPhones. They have a rule that if you put an iPhone on a non-iPhone plan they switch you to the iPhone plan automatically (they can tell which model you're using). I don't know if they allow iPhones on prepaid plans; they definitely don't sell any of their own this way. You could consider a month-to-month plan instead, and it would probably be cheaper if you're going to use a lot of data.