Viber is a voice-over-Internet app that's seen some success on iOS already, but today the company announced a brand new version for both OS X and Windows. Viber Desktop has all of the features of the iOS app, including free messages and calls to other users, synced contacts and history between the mobile and desktop clients, and the ability to start up group conversations and so on. The iOS version and the desktop version are completely integrated, so you can even start a call on one platform, and then transfer it across to another. Both versions are co
