Rob,
Postal Bar codes from a ZIP+4 will not fit on an Avery 5160 Address label.
You will have to use an Avery 8161. This was true in Word 97, 2000, 2002 and
2003. You can't change the size as you would font sizes. The bar code must
match the U.S. Postal Service specificaitons.
Next point regarding the printing of the bar codes. There will be no postal
savings to you unless you apply for a Bulk Mail permit and have your
addresses certified by a mailing house for a fee. Sure, programs to do this
are available for hundreds of dollars and the semi-annual update fee is
horrenderous. Ask for the U.S. Postal Services Domestic Mail Manual 200
Series at your Post Office.