Facebook promised that their updated Facebook Messenger app would allow iPhone users to call one another for free thanks to the magic of VOIP calls. The feature has been rolled out to other countries, but Facebook just rolled it out to the U.S. today.
The Free Call feature allows you to call any of your Facebook friends who are also using the Facebook Messenger app. Rather than using the minutes on your cellular plan, the calls are made using your data connection so you’re not using up any minutes.