Excel 2003

I want cell G4 conditionally formatted if a zero (0) is entered, but
no action if left blank. To simply program "G4=0" formats the cell
when empty because zero and null evaluated as the same? But when I use
this formula it works...

=AND(G4<"",G4=0)

So, is this the recommended hoop to jump through to make it work or is
there a better way?

Thanks,
Melina