Today Mozilla Labs has released a new experimental add-on for Firefox, called Rainbow, which will enable video and audio recording in the browser.
The recorded media will be in an open-source format. Theora for video and Vorbis for audio in an Ogg contanier. The file can then be accessed in DOM using HTML5 File APIs and then be uploaded to a server.
This pre-alpha version of the add-on will work only with the Firefox nightly builds on Mac but support for Windows and Linux will be added soon. Mozilla also wants to enable live streaming of video feeds.