Folks, an MSDN TV presentation can be found here.

Brief Description
This presentation covers the reasons behind Excel Services, the benefits of using them, and a demonstration of using a Web service to incorporate Excel-based business logic into your own server solutions.
 
Overview
Excel Services let users calculate, display, and explore Excel workbooks on the server side. This presentation covers the reasons behind Excel Services, the benefits of using them, and a demonstration of using a Web service to incorporate Excel-based business logic into your own server solutions.
 
- Keith