wireless providers

[cuneo]

i'm not sure if i'm in the right forum.. so feel free to move me if i'm not.
i'm from italy, and even if i'm moving to florida in the next month, i'm not familiar with the wireless providers in the usa. i know iphone can only be purchased with at&t.. but i'd like to know from you which are the other providers which have good plans offering unlimited data/email traffic. plans that could be applied to a smartphone or to an unlocked iphone.. but mainly to an other smartphone. i'm trying to compare the different things before buying an useless phone 
thanks a lot
andrea

[cjs]

Your main other option in the US for GSM (unlocked iPhone) would be T-Mobile. T-Mobile has always been well known for offering affordable data plans. I'd check them out. Many US T-Mobile customers are using unlocked iPhones on the T-Mobile network.

[cuneo]

exactely what i was looking for!! 
i already checked the tmobile website.. but i couldn't find out..
do you think that a combination of unlimited data with few calls and sms from tmobile would be cheaper than the 60 dollars of at&t?
thanks!!
andrea