This talk is almost a year old, but Lawrence Lessig has just put out a video, with his voice synchronized to visuals of his slides. Not only is the content important, but his presentation format is compelling and effective.
Oh, and the video is being distributed using the YouTube-like YouAre.tv (see player below), which includes Creative Commons licensing in its upload process. Blip.tv has had this feature for awhile now, and its something we’re including in Openomic, as well.
It is also available as Torrent.