Google announced that there will be a licensing service for applications in the Android Market Place to shield that Apps can be copied and spread without charges. That way Google reacts on the sustained criticism of many developers that it is to easy for users to exchange apps illegally.
In the future the licensing service will synchronize the data with the Google server to detect if users are legitimized to use the software. If the opposite is true the app will withdraw the service.
So you can be glad that the FriendCaller App, which enables you free international calls, is for free!