candace
try the excel help topic called "moving average analysis tool and formula". apart from figuring out what interval to use (setting it at '2' will average a given cell ref and the previous cell contents, '3' will average the cell ref and the previous 2 cells contents, etc) it's pretty much plug in the input and output ranges. leave about as much space for the output range as for your input range and you shouldn't overwrite anything.
good luck
I may not have understood what you're after, but try this.
If your data starts in A1, put this in B1 and fill down :-
=SUM($A$1:$A1)/COUNT($A$1:$A1)
Omar,
That would produce a "running average". For "moving average", see Tools|Data Analysis.
Aladin