Gmail Voice and Video chat has now even more features. You can now call any phones in the US and Canada right from your Gmail account, and that too for free! Previously both users at the two ends required computers to communicate using the application. Dialing a phone number now is as easy as calling from a conventional phone. The newly included dialpad is as simple as it can get.

Although calling to other countries is perfectly allowed, however there is a charge involved. The complete list of countries supported and their corresponding rates are given here.

[source: googleblog.blogspot.com]