I have an application that could use a feature that would increment or
decrement the contents of a specific cell, by clicking on buttons somewhere.
The ideal place would be cells right next to the number cell, but if there
were the ability to add a couple of buttons to the toolbar that could be set
to refer to any specific cell, that would work.

Since I don't have VBA, I am looking for an existing function, in the
current Excel 2003 or the next version, that would have these functions in
the function library supplied with the spreadsheet itself.

The specific application invloves using a cell as an index into the rows on
a different Sheet, so that the current sheet can extract and display
information from that row, with the ease of single-click stepping through the
rows.