AT&T Call International lets that network’s customers make long distance calls from the U.S. to international numbers. You can expect to pay $0.04 to $0.09 per minute for calls to wirelines (depending on the country), or up to $0.27 a minute to other cellphones. You can also use the app to make calls while you’re abroad, at the same rates, but those calls require you to be connected to a Wi-Fi network.
Call International is available in the App Store now. (It’s also available for Android and Blackberry.) Once you download the app, it will set you up with an AT&T Call International account. Once that’s done, calls can be made either from the app itself or from your phone’s contact list. (In the first case, you still have to insert the correct international calling code when dialing the number.)