The new product was made possible through Google's acquisition of the Swedish e-meeting startup Marratech last year and a licensing agreement with New Jersey start-up Vidyo. Serge Lachapelle, the Swedish Google product manager in this video had been the VP of product management at Marratech.
From the Google System blog:
"As anticipated in the post about Gmail SMS, video chat is the next big that will be added to Gmail. Justin Uberti says that video chat will be added today, along with voice chat. "We've tried to make this an easy-to-use, seamless experience, with high-quality audio and video. And we've built this product using Internet standards, such as XMPP, RTP, and the newly-standardized H.264/SVC video codec." To try the new features go to http://mail.google.com/videochat and install the required plug-in (Windows & Mac-only, for now). After restarting the browser, open Gmail, select a contact from the chat section and see if there's an option named "Video & more". If you can't find this option, your friend didn't install the plug-in yet."
Like other video chat solutions you'll need a web cam and microphone and download the plug-in. It uses about 300 kbps for bidirectional video and works with browsers that support the current version of Gmail: Chrome, Firefox 2.0+, Internet Explorer 7.0, and Safari 3.0 but there are no plans for a Linux-based plug-in. Unlike Skype Premium or ooVoo, Gmail Video and Voice does not connect to regular phone numbers and only to other Gmail users. There's currently no recording option and only capability to conferences with two people.
Learn more: http://www.google.com/mail/help/videochat/learnmore.html