Zip Code Problems

I've got a list of 40,000 zip codes and I'm tryingf to link them to
counties

> using VLOOKUP. The problem is that the source list is formatted as general

> and actually contains a "0" before Zip codes that begin with a "0". My
data

> list contains ZIP codes that while the value in the cell may be1928, for

> example, I've got the cells formatted as Special>Zip Code, so it displays

> as )1928. So, I trimmed the preceeding zeros off of my source list and

> formatted the cells as Special>Zip Code. NOW, here's the problem. In order

> to get the cells to actually be formatted like Zip Codes, I have to

> double-click (or edit the cell by pressing F2) the hit enter. I don't have

> to change the cell in any way, just click in it, then click out of it,
then

> Excel formats it appropriately. As you can imagine, I'm not too excited

> about doing this 40,000 times and I can't figure out how to automate the

> process through a macro.

>

> Any ideas???

>