You can hide 0's with the technique that John suggested, but there are other
ways, too.
You could change the formula so that you see what looks like an empty cell:
=if(yourformula=0,"",yourformula)
You could mask the 0 (it'll still be there) with:
Format|cells|Number tab|Custom category
General;-General;;@
(positive; negative;0's;text)
Or:
format|conditional formatting.
value is = 0
and use the same font color as the fill color (white on white?)
