Mozilla, Google and Opera have been working on WebRTC for a while now. Considering that it's one of the most ambitious web technologies of late, it's understandable.
WebRTC, as the name suggests, is designed to enable real-time web communications, video and audio.
The plan is to enable developers to build apps that enable audio and video chat, without the need for a central server, and all with standard technology supported by the browser.
WebRTC is made up out of several components. The MediaStream is the technology that enables browsers to access the webcam and the microphone on a computer.
The other two main components of WebRTC are a bit trickier to implement, they handle the peer-to-peer data connection and establishing that connection between two browsers.
The WebRTC API is almost ready to go and is close to becoming a W3C recommendation, the first step towards becoming an officially ratified standard. Microsoft has its own ideas on the technology.
Things are coming together and Mozilla is now highlighting some of the progress with WebRTC and also announcing plans to have it built into Firefox 18, which is already in the Nightly channel. Firefox 18 is supposed to land in the stable channel in January next year.
Especially with a project this complex, things can get delayed, so don't count on WebRTC definitely being built into Firefox 18, it may get pushed to Firefox 19 and beyond, or just some components may land.
Whatever the case, WebRTC is only months away from becoming a reality. Chrome and Opera haven't announced clear plans or deadlines on supporting WebRTC, but it's safe to say that it's going to land in the stable releases at around the same time.