BigBlueButton is an open source web conferencing system for on-line learning. We believe that every student with a web browser should have access to a high-quality on-line learning experience. We intend to make that possible with BigBlueButton.
BigBlueButton supports real-time sharing of slides (PDF and any document readable by OpenOffice), webcams, whiteboard, chat, voice over IP (using FreeSWITCH), and desktop. It can record and playback all content shared in a session. The BigBlueButton project is is supported by a [community of developers] (http://www.bigbluebutton.org/support/) that care about good design and a streamlined user experience.
After watching the videos, if you want to immediately try out BigBlueButton, the project maintains a live [demo server] (http://demo.bigbluebutton.org) that anyone can join.
If you like the work we've done with BigBlueButton and would like to contribute improvemets to the project, see [Contribute to BigBlueButton] (http://code.google.com/p/bigbluebutton/wiki/FAQ#Contributing_to_BigBlueButton).