To view recordings(podcasts) of all kinds of interesting demos and interviews direct from TechEd USA click here
Thanks to Paul Fallon's post for providing the URL of the site listed above.
As Mike Hall explains "A podcast is an audio or video file that you can subscribe to online."
For me such Podcasts are an interesting phenomonen as they are freely available recordings made by people like you and I who attend events and wish to share their experience with others.
As the post on ITEdge points out you can subscribe to the site(for free) and hence automatically be made aware of new content.