First note that zipfile is a plain Python module, so reading Python.../Lib/zipfile.py will reveal all its secrets.
I don't think it is possible to replace archive members using the module. You could copy all the files into a new zip file, replacing the ones you want to change as you go. But it might be easier just to use os.system() or something similar to run an external zip program. -- http://mail.python.org/mailman/listinfo/python-list
