The app is called the ePhone and it is developed by Comwave. The app even allows for free video calls to other ePhone users. The bad news is that unlike other VoIP apps such as Viber, Comwave ePhone will not be free and will come at a subscription fee of $20 per year, although first time users will be able to enjoy a 30 day trial with 100 free minutes to over 60 countries. Purchasing the app will then net you 250 minutes per month in talk time.
If you're interested in getting your hands on the Comwave ePhone app for your Blackberry Playbook, then just head on down to the Blackberry App World to get your copy today.
source: Ubergizmo