When you need to build a distribution package of a Zope Product, you need to make a copy of your working Product directory, then clean it up (remove "pyc", "bak" "*~" files and all the CVS stuffs), the you tar-gzip/tar-bzip2/zip this directory.
The package_product.py does all this for you in one shot.
This is not a Zope Product. Install it in your $SOFTWARE_HOME/utilities.
The command...
$ python package_product.py --help
...shows all you need to know to use it.
Enjoy !