Spreadsheet Professional

Spreadsheet Professional is an Excel Addin that works with all versions of Excel from Excel 95 to Excel 2007. It has been designed to radically reduce the costs of developing spreadsheet and increasing their quality by: 
automatically testing for the most common errors
generating a full set of spreadsheet documentation providing tools to help build spreadsheet models more accurately and quickly providing tools to assist in the use of the spreadsheet enabling you to compare two spreadsheets for differences in inputs, formulas and results