Previously Gmail allowed us to call to USA and Canada phones via Gtalk but now they have stopped their service. Only people inside USA and Canada can use that service now. But I found a skype-type software called KNCTR which lets us make phone calls for free to US+CA from any country (as long as we have Wi-Fi). Thought people outside US might need it. Just google 'KNCTR' and you will get it. Thanks!