We have a SharePoint 2007 deployment which will have a substantially large document library. My client wants the ability to export this library to an Excel spreadsheet, but specifically wants the ability to divide the spreadsheet into several worksheets based on a specific field. Is this possible to accomplish in WSS 3.0, through the object model or otherwise?

There is a out-of-the-box Export to Spreadsheet, but it does not appear to support automated subdivision of the list items into separate worksheets. I do not know if Excel Services that come with MOSS are capable of it, but we do not have MOSS so we cannot consider it an option for now.