While this is a program that probably makes more sense to do in C 
(using something like http://github.com/mattn/gntp-send ) I've done
the first version in Python so I could have a working program.

Requires the python GNTP library that I wrote http://github.com/kfdm/gntp

Usage: gntp-tee.py [options]

Options:
  -h, --help            show this help message and exit
  -H HOST, --hostname=HOST
                        Destination Host
  -p PORT, --port=PORT  Destination Port
  -P PASSWORD, --password=PASSWORD
                        GNTP Password
  -A APP, --appname=APP
                        GNTP Application Name
  -v                    Print Debugging to stderr