Seb, a buddy of mine, runs Altus Learning Systems, a company that take presentations and makes them into an easy to use format for the web. He recently helped sponsor Enterprise 2.0 and had his company record 14 presentations and has made them available on the web for free.
The presentations combine a video recording of the speaker, the slides of the presentation, and a full transcript of the talk. All time indexed, searchable, and with shuttle capability. There's even a way to speed up the talk to hear it faster than realtime. There are even links to download the content as MP3s, MP4s, Powerpoint, etc.
Dave Weinberger's talk is great, as expected. But the rest of the speakers are good as well. For free, what have you got to lose?
The presenter works best in IE, but it is Firefox and Mac compatible as well.
If only all tech conference's offered this kind of easy to use recording of talks...