When talking to 9to5Mac, a T-Mobile spokesperson offered up a tidbit of information that suggests the #4 wireless carrier, which does not sell the popular Apple smartphone, is home to over a million iPhones. Most of the devices are older iPhone models, though a fair amount of customers have reportedly trimmed down their T-Mobile SIM to fit in the microSIM slot of the iPhone 4.
Since T-Mobile does not offer the iPhone 4 and uses the AWS band for its 3G network, these iPhone models are unlocked and running on EDGE. It's not a pretty situation, but it gets the job done for those T-Mobile customers that must have the iPhone. As for the possibility of a future iPhone, the T-Mobile spokesperson was tight-lipped and would only say there is nothing to announce at this time.