Andy Pope has a sample workbook that may help you:

Shade area between lines
http://www.andypope.info/ngs/ng21.htm

Petrus Van den Cruyce wrote:
I made some graphs in excel and i must say there looking good. I want
to colour in an area whose bounderies are :
those who have less then a number on the x-scale and less then an other
numer on the y-scale.

--
Debra Dalgleish
Excel FAQ, Tips & Book List
http://www.contextures.com/tiptech.html