Go to page 4 at http://commnet.microsoftpdc.com/content/sessions.aspx and you will find this little tidbit...

Longhorn Media Center: Developing for the 10-Foot Interface
Learn about the new extensibility model for building 10-foot (TV oriented) applications and services for the Longhorn Media Center Edition. This session includes integration into the product, design elements, and coding of samples using Avalon.

Hope to see you there!