The Viber client software is available for Android, iOS, Series 40, BlackBerry OS, Symbian, Bada and Windows Phone. Viber works on both 3G and WiFi networks. Once installed, it creates a user account using one’s phone number as username. Viber synchronizes with the phone’s address book, so users do not need to add contacts in a separate book.

Its redesigned VoIP application now supports free calls with HD audio for Windows Phone 8. Looks like its trying to catch up with its Android and iOS counterparts. Until now its key feature, the free voice calls between users was only available on Android and iOS and not on Windows Phone.

The new version also locks screen notifications and has the ability to pin conversations to your Start screen.

It also includes picture sharing and group conversations with up to 40 people.

Some see Vider as a serious competitor to Skype, although I think there is a long way still. Viber is a great alternative to Skype though which works quietly at the background at all times without having the app explicitly open. So if you don’t like Skype running in the background for whatever reason, do check out Viber.