Google

Call phones from Gmail

Install voice and video chat

Requires Windows XP+ / Mac OS X 10.4+ / Linux

Try it now

Click above to be taken to Gmail

Free to the US Call phones in the US and Canada for free.
Cheap international calls Call around the world for pennies per minute
Video chat, too Install the plugin and get video chat for free

Free domestic calls within the US and Canada and low rates for other countries with this small plugin – right from within Gmail.

This feature is currently not available in all locations.