Hello, I will be visiting the US in about a month and I will be staying there for about 3 weeks. Since I plan to visit 4 cities it would be great if I had a data plan with my iPhone 4S (unlocked) for google maps and some smaller stuff. I am not familiar with any of the US plans but I'd be grateful for some recommendations. As far as I can tell so far AT&T has the fastest network and the best coverage (despite the fact that their network took the most heat about a year ago). Can anyone recommend any data plan prepaid SIM cards I could use while in the US? Affordability would also be a important factor (given the fact that I'm a student). Thanks in advance and I'm looking foreword to visit the US.