The missing parts have finally arrived and Gmail is now equipped with voice and video chat. If you have a microphone and a webcam, you can now video chat with your friends directly from Gmail by downloading and installing a special plugin.
The Gmail voice and video chat plugin supports all major browsers which includes Firefox. It gets installed automatically on all the browsers.
The plugin at present works only on on Windows, hopefully in future, it'll will also work on MacOS and Linux.
Unlike Skype though, The Gmail voice and video chat doesn't support direct calls to telephone. But anyway having a PC to PC voice and video chat from Gmail is definitely advantageous.
You may download Gmail Voice And Video Video Plugin By Clicking On This Link