FreeXL is an open source library to extract valid data from within an
Excel (.xls) spreadsheet. FreeXL design goals:
 * to be simple and lightweight
 * to be stable, robust and efficient
 * to be easily and universally portable
 * completely ignoring any GUI-related oddity

Note that the final goal means that FreeXL ignores at all fonts, sizes
and alignments, and most formats. It ignores Pivot Table, Charts, Formulas,
Visual Basic macros and so on. FreeXL is structurally simple and quite
light-weight (typically 40-80K of object code, stripped).