My plan has limited minutes and international calling is obviously atrociously expensive. So Skype comes to mind. However on PC to PC calling it seems to work pretty crappy despite excellent connections. For example Facetime seems to work a lot better. For voice calling BBM Voice has been astounding. Skype used too be very good when I started using it but now it seems just OK, maybe its server load or something. On top of all this the windows phone app is in preview still. How have you found voice calling quality through Skype on windows phone? Is it at least as good as regular phone calling?