I see that Keith Combs has posted the slide decks from his recent presentations on Longhorn Server to his blog here: http://blogs.technet.com/keithcombs/archive/2007/04/02/windows-connections-conference-slides-posted.aspx
Windows Server code name "Longhorn" Tech Overview Part 1
Windows Server code name "Longhorn" Tech Overview Part 2
Windows Server code name "Longhorn" Network Access Protection (NAP)
Windows Deployment Services
Keith is really fun to listen to, and I get a lot out of watching his webcasts on Technet. To view an upcoming calendar of the webcasts he will be delivering, click here.