Facebook has updated the iOS version of its Messenger app to allow iPhone users to make free calls to the US over Wi-Fi or cellular networks. The update is expected to be rolled out to Android and BlackBerry in the coming weeks. IN fact, the feature is being slowly rolled out to iPhone users, with not everyone able to use the feature quite yet.

To make a call from the iOS app, select the "i" button and select Free Call. This feature is a direct competitor to Google Voice, a service by Google that allows users to make free calls to the US. Google Voice was a lifesaver--and wallet saver--for me while I was in Europe, so having the ability to use my iPhone would be that much better.

However, the app isn't quite as good as Google Voice. To use the free calling, it requires a user's friends to have the app installed on their iPhone and it cannot call a landline, unlike Google Voice. Facebook has stated they are working on an update for BlackBerry and Android to bring the same functionality to those ecosystems.