Two new links – one to the official Excel blog, and one to Shahar Prish’s personal blog. Definitely check out Shahar’s blog – he’s a bit of a Renaissance man… one of the big brains behind Excel Services, but also one of the co-inventors of the method that enabled us to embed the PowerPivot db directly in the Excel file, which makes him a personal hero of mine 
Excel blog post: http://blogs.msdn.com/excel/archive/2009/11/09/excel-services-in-sharepoint-2010-rest-api-examples.aspx
Shahar’s blog: http://blogs.msdn.com/cumgranosalis/
