Live video webcasting through the browser, cross-platform, is slowly becoming a working technology due to recent developments in browser specs, as part of the advancements of HTML5.
Several browser manufacturers (Google, Mozilla, Opera) are currently exploring methods to bring two-way multimedia capacity to web-browsers. The technical name for this technology is WebRTC (Web Real-Time Communication).
Here is a quick overview of current initiatives that look promising:
“an experiment around real-time voice and video communication built on WebKitGTK+”
While being part of the WebRTC working groups, technicians at Ericsson Labs have implemented their own experimental prototype. It is running in “a modified version of WebKit”, under Ubuntu:
First release: March 2010
“Rainbow is an early prototype that provides video and audio capture capabilities to web pages. It is currently distributed as a highly experimental Firefox addon.”
Major update, August 2011:
First release: October 2010
The WebRTC initiative
An open-source effort, started by Google in June 2011, that provides many of the low-level platform APIs required to build support for real-time communication into browsers.