New MSDN Article on Extending Excel Services Through UDFs
From yours truly:
Summary: Optimize version 1 of the Excel Services programmability framework to extend Microsoft Office Excel 2007 and Excel Services functionalities to work with SharePoint lists, query tables on Excel Services, external workbook references, SQL write-back, and user-defined functions (UDFs).
NOTE: I already caught a few mistakes that the editing process introduced (like the one in the summary about working with UDFs being an "extension")... but the content should still be intact :o)... I'll go over it and make some requests to clean it up when I get a chance.
NOTE 2: I just found out that the article isn't supposed to be published yet, hence the mistakes I've been catching. The article that's live is a Draft copy... we're just going to leave it up and replace it with the final version once that's ready which should only take a few days.