Viber is an application that looks like an instant messenger, but is designed to make phone calls for free, using internet, instead cellular networks.
Using this application, you can communicate only with users that also have this app installed. You are able to call users from any country, view their faces in HD format using video call feature, send text or multimedia messages.
Allows to synchronize contacts list between mobile device and computer. You can use this app from computer or a mobile device.