xlsLib is a multiplatform, C++ developed, library for dynamically 
generating Excel(TM) files (*.xls). It allows the generation of Excel(TM) 
compatible files without the need of any other external software.

    * Easy to use, fully object oriented, API.
    * Excel 95 (TM) format spreadsheets.
    * Multiple worksheets.
    * All standard font's styles and colors.
    * All standard cell's styles, colors and properties.
    * All standard cell's border-styles and colors.
    * Three basic type of cells:
          o Blank.
          o Label. The text in labels can be formated in all standard styles.
          o Number. All standard number-formats are supported.
    * Merged cells.
    * Handling of cells using ranges.

WWW: http://xlslib.sourceforge.net/