I agreed with what has been posted, but some further info:

3of9 BarCode font (the most popular) requires an asterisk (*) atr either end as begin and end characters.

Beware of certain shareware fonts, some can't handle spaces and other odd characters.

If for some reason you're going to be using UPC BarCodes (like the ones on the sides of your soda can), the last digit is a checksum digit and there's an exact formula for detetmining it (don't have it any more -- needed it for a job a few years back).

Hope this helps.

-John Kiernan