Of course, this depends entirely on whether your facebook friends really are your 'friends'..

Amplify’d from news.smh.com.au

Vonage makes free Facebook phone call app

Vonage is releasing an application for the iPhone and Android phones that provides free calls between Facebook users.

The application from Vonage Holdings Corp. is another step in the industrywide move away from the traditional phone system and its numbers _ and toward Internet calling.

Vonage Mobile for Facebook is available Wednesday as a free download for iPhone, iPod Touch and Android phone users.

They sign in with their Facebook username and see a list of Facebook friends who also have the app. Tapping a name places a call to the friend, whose phone rings. The app doesn't need to be running on the friend's phone for the call to go through. Read more at news.smh.com.au