After been using Viber for some time now. We highly recommend this mobile application for all smartphone users. Viber is an mobile application for iPhone® and Android™ phones, a dialer/communications replacement app that lets you make free phone calls and send text messages to anyone in the world who also has the application installed. This allows you to cut the expensive voice and text plans to the bare minimum.
The call log shows everything, not just calls made through Viber, which is why this can be a full-on dialer replacement. When you launch it, you can see your recent/missed call list, your contacts, the keypad/dialer, messages. It uses your own phone number as your Viber number and scans your phonebook for contacts already using Viber and more, gives you a list of items such as inviting friends to join you on the service and sharing it on Facebook and Twitter.
The contacts section will also bring up all of your contacts, letting you sort them by showing only those who are also on Viber, all of them at once, or only the ones you designate as favorites, which also includes, at the bottom, your frequently contacted list of numbers. For anyone who is on Viber in the non-Viber exclusive lists, a small icon will show next to their name.
The sound quality is very good, but a bit too low. Inside sources have confirmed that this will be corrected in the very near future.
Soon it will also be available for BlackBerry users!
Download the app here: Viber.com