Make free calls to US & UK with Google talks

In addition to sharing voice and video chats with your contacts from computer to computer, you can also place and receive phone calls to any landline or mobile phone number in Gmail.

To get started, you must be signed in to chat and have the voice and video chat plug-in installed.

Simply click the Call phone link at the top of your Chat roster to open up the Call window.

From the Call window you can dial a phone number, view your call history or add credit if you'd like to place an international call. Additionally, if you are a Google Voice user, you can enable Google Chat as a forwarding phone and receive calls in Gmail.

If you don't want to see the Call phone option in your Chat roster, you can disable it.