Excel 2003 SP3

I have a couple of columns, such as WorkType and ZipCode that have leading
zeroes. For example, a ZipCode could be '00141', '02099' etc. and the
WorkType could be '0800', '1000', '0100' etc. I've changed the column format
from General to Special ('00000') and tried Text and also tried saving as CSV
(MS-DOS). I can't setup the entire spreadsheet as Text or whatever because I
have a column of dates and times, phone numbers, city, ....

What's the way to save a spreadsheet so that my columns with leading zeroes
in the cell don't get dropped? Seems easy and I remember doing this a while
back but I can't seem to find the solution now....! :-(
TIA!