WANTING LEFTOVERS: T-Mobile USA, the only "Big 4" phone company that doesn't sell the iPhone, will start advertising that AT&T iPhone owners who are out of contract can switch to T-Mobile.
THE CATCH: iPhones suffer a big penalty in data speeds on T-Mobile networks. T-Mobile is reshuffling the frequencies on its network, which will let it match or even exceed AT&T's data speeds on iPhones. For now, that will be evident only in a few spots.
THE ADVANTAGE: T-Mobile's pitch will center on its unlimited data plan. AT&T stopped signing up new customers to unlimited plans two years ago.