Viber - Free Phone Calls is, as it's name indicates, an application that allows you to make phone calls for free.

To use it, of course, you will need to have a compatible Android device with WiFi connection, and the contact that you wish to call must also have to the application installed on their device. If not, then you will not be able to contact them using the service.

Once you have the app on your device, all you have to do is let it access your contacts and, in a matter of seconds, you will be able to make phone calls with pretty good audio without paying for anything other than the Internet connection, for which WiFi is recommended as opposed to 3G, being that using 3G you will probably spend more on data fees than you would for the phone.

Viber - Free Phone Calls is a very useful app that allows its users to save a lot of money on phone calls. What's more, it is very easy to use and configures your contacts automatically. All very comfortable.