Are you using MOSS (Office SharePoint Server) 2007 Enterprise (with Excel Services)?
If so, just create "the perfect worksheet" in Excel, save it to a document library, then users can view it either in Excel (locally on the client from the library) or using "View with Web Browser" in which case Excel Services will render it.
So SharePoint (WSS or MOSS) is just "storing" the perfect Excel worksheet that does the work. IF you have MOSS/Excel Services, it can render that sheet to a web browser.
Dan Holme
Office & SharePoint Pro Community Leader
MVP (Windows Server - Directory Services)