Google Voice and Video Chat can no longer be downloaded.
In my mind Gmail is undoubtedly the best Web-based email client out there, but the one thing it always lacked was video and voice calling.
Google Voice and Video solves this problem and as you'd expect from a Google product, it works extremely simply and effectively. Getting setup is extremely easy. You'll need a webcam of course but all you have to do is download the voice and video plug-in, quit all open browser windows, and install it.
Once done, simply sign into Gmail and select the contact you want to call. You can see immediately if they have a voice and video capability because there will be a yellow camera icon next to their name. If they don't, you can you can invite them to download the Gmail voice and video chat plug-in from the 'Video & More' menu in a chat window. If they don't have a webcam, you can still make voice calls.
Like everything else in Gmail, Google Voice and Video works extremely well and provides excellent quality video and audio to your webchats.