Myrna Larson and Bill Manville have developed a compare that's very nice.
http://www.cpearson.com/excel/whatsnew.htm
look for compare.xla
But the bad news is that this does a cell-by-cell comparison against two
worksheets--not workbooks. A1 compares to A1, x99 to x99, etc.
If you insert/delete a row or column, then this won't work very well.
=======
Other alternatives that may work depending on what kind of differences you're
looking for:
Save each worksheet as a .csv file and use any comparison program you want to
compare two text files--like MSWord.
