Excel before Excel 2007 definitely does not have the ability to
trigger and Event on a cell format change.

And I wonder what you would do if column B is selected and
the entire column is reformatted, which BTW is a lot more efficient
than to format the few cells in a column that you actually use.

Clear Formats will trigger a change event at least in Excel 2007,
but that isn't going to do you much good.
--
HTH,
David McRitchie, Microsoft MVP -- Excel
My Excel Pages: http://www.mvps.org/dmcritchie/excel/excel.htm

"Zone" ...
Lots of posters, myself included, would like to trigger an event when a
user makes a change in sheet formatting, like changing the interior color
of cells. Of course, Excel doesn't consider changing cell formatting a
worksheet change. The only thing I can see that changes is the workbook's
saved status, and a change in that won't trigger an event. Any
suggestions? James