Just when it looks like the wireless carriers are putting the squeeze on you, here comes T-Mobile. T-Mobile has this VoIP service called Bobsled - launched earlier this year, but now there are mobile apps. When it was first launched, Bobsled was designed to let you have voice calls with your Facebook friends. The service also works on browsers. From Gizmodo: "The browser app (which will work for OSX and Windows in virtually any browser) allows you to call any phone number in the U.S., Canada, and Puerto Rico, for free. The kicker here is that you don't have to be within one of those countries to use it, so if you have family in Albania, they can use this web service to call you on your home phone in Alabama and it won't cost a thing."
Today, you can get the app from your iPhone or Android device. Again from Gizmodo: "They aren't yet as fully capable as the browser apps in that they cannot dial out to regular phone numbers, but I was told that capability will be coming by the end of the year. In the meantime, you can make and receive Bobsled calls on any of your iOS or Android devices. When someone calls you, all of your devices that have the app will ring at once. You answer on the one you want, then the rest of them will be automatically silenced."