GNU barcode is a tool to convert text strings to printed bars. It 
supports a variety of standard codes to represent the textual strings
and creates postscript output.

Main features of GNU Barcode:

* Available as both a library and an executable program
* Supports UPC, EAN, ISBN, CODE39 and other encoding standards
* Postscript and Encapsulated Postscript output
* Accepts sizes and positions as inches, centimeters, millimeters
* Can create tables of barcodes (to print labels on sticker pages)

WWW: http://www.gnu.org/software/barcode/