FlexCel Studio for VCL allows you to create Excel files by substituting values from a database or variables into a template. There is also an extensive API allowing to directly read/write Excel files, a grid for displaying and editing them. If you need to read or create complex spreadsheets, on Windows, Linux or Mac OSX on machines without Excel installed, Flexcel can do the job.
FlexCel Studio for VCL can create completly native (no OLE/dlls) files (biff 8 format: XLS 97-2003-XP) and can write images/comments/conditional formats/merged cells/pivot tables/charts and almost the complete Excel 2003 feature set in native mode