another formula question

From: No (no_at_isp.com)
Date: 02/27/05 

Date: Sun, 27 Feb 2005 05:13:09 -0600

I know how to do a basic formula that adds 2 cells but when I drag that
formula down to copy it to other cells where there is no total due to no
data entered yet it shows $0.00.

  besides +A1+B1 is there anything else that I can add to the formula so
that the cell is blank untill there is a total to display, in other words,
get rid of the $0.00 in all the cells