T-Mobile is the 4th largest wireless carrier in the United States, serving over 30 million customers. T-Mobile uses GSM technology --- most of the company's phones will work seamlessly on wireless networks in dozens of countries around the world. T-Mobile has a 'value' strategy and offers a set of traditional rate plans that, in most cases, offer more minutes for the money than other wireless carriers. The carrier also offers a series of myFaves rate plans. These plans give the subscriber unlimited calling to any 5 numbers. These numbers need not be T-Mobile customers and don't even have to be cell phone numbers.