FYI you can view and/or download PDC 2008 sessions from this page. The user interface is not entirely intuitive, so here’s an example:
I’ve selected an IE session from the session calendar/list:
Next, click on the tiny > icon next to the session name under the “Your selected session”; that will launch another browser instance, with the session streaming via Silverlight. Underneath the player window, you’ll see:
Click on the “Powerpoint Deck” link to launch the pptx file. Note that the sessions are generally posted within 24 hours of the related live presentation.