I found this app recently for my Android phone. It's called Viber. With it you can call your friends and family for free. It will import all your contacts, sync personal details and accounts. And the most awesome feature is it's sound quality. Calls sound a lot better than my regular carrier. Of course to use it you'll need access to mobile data services or WiFi. I should also mention that it doesn't consume much bandwidth. I think it's in the range of 240KB per minute up and down. That's about 14MB an hour. Pretty neat.
Follow this link to the Android Market
or Scan this QR with your phone to get the App: