I think we use this: http://pypi.python.org/pypi/chishop/

You just set it up on a local server, and upload packages the same way they are uploaded to real PyPI.

    python setup.py register sdist upload

You can specify alternate PyPI server with a ~/.pypirc. There are probably other ways to do this. What's nice about this is you can upload your own private packages or your own personal forks of packages. We do both.