Here's some useful information, borrowed from the Windows Connected blog.
Keynote – Ray Ozzie, Amitabh Srivastava, Bob Muglia and David Thompson
Monday, October 27 11:30am-1:30pm Eastern Time
UPDATE: The key note is available on-demand now using Windows Media Player via the links above or using Silverlight at the Microsoft PDC site.
Keynote - Ray Ozzie, Steven Sinofsky, Scott Guthrie and David Treadwell
Tuesday, October 28 11:30am-1:30pm Eastern Time
PDC 2008 Live Blog
UPDATE: Here's the transcript from the first keynote.