Summary Box: T-Mobile network to work with iPhone

CHANGES COMING: T-Mobile USA will revamp its wireless data network this year, with the side effect of making it compatible with iPhones and some other smartphones sold by competing carriers.

WHAT THIS MEANS: T-Mobile is the only nationwide carrier that doesn't sell the iPhone. Soon, iPhone 4S users could migrate over from Sprint Nextel Corp. and Verizon Wireless when their contracts expire. Owners of AT&T Inc. iPhones could, too, if they figure out how to "unlock" their phones from AT&T's network.

ONE MORE EFFECT: Many international visitors will be able to use their smartphones on T-Mobile's network.