TechNetCast is making available the audio tracks for the keynote speeches given at the recent O'Reilly Emerging Technology Conference. As I log this URL, only four are available, but the rest of them are promised within days. (Hopefully that will include Steven Johnson ...)

The keynotes include:

Rethinking The Modern Operating System, by Richard Rashid, Microsoft.
Fixing Network Security by Hacking the Business Climate, by Bruce Schneier.
Autonomic Computing, by Robert Morris, IBM.
The Shape of Things to Come, by Tim O'Reilly.