Viber is an iPhone and Android application that lets you make free phone calls and send free text messages to other users that have Viber installed. When you use Viber, your phone calls to any other Viber user are free, and the sound quality is much better than a regular call. You can call any Viber user, anywhere in the world, for free and now also text them.
Viber uses your phone number as your “identity” and lets you make free Viber phone calls to any of your friends that have Viber – using their phone number. When I installed Viber in my phone, it identified all my contacts who have Vider installed too.
It took me about two minutes from the time I made a clicked install on the Android market to make my first phone call.