Maybe you know San Diego TechEd 2004 is closed. Maybe you also know that during TechEd few sessions were about Virtual PC 2004 and upcoming Virtual Server 2005. To be exact here the sessions list about both products and relative slide, videos and hands on lab:

Virtual Server 2005 Technical Overview	Slides & Videos	HoL
Advanced Configuration Scenarios for Virtual Server 2005	Slides & Videos	HoL
Using Microsoft Virtual Server 2005 to Install a 2-Node Cluster of Virtual Machines	Slides & Videos	HoL
Advanced Desktop Testing Scenarios with Virtual PC 2004	Slides & Videos	HoL