pypi compatible software

[Aljosa Mohorovic]

i've been searching for a recommended way to setup private pypi
repository and i've found several options:
- PloneSoftwareCenter
- http://code.google.com/p/pypione/
- http://pypi.python.org/pypi/haufe.eggserver
- http://www.chrisarndt.de/projects/eggbasket/
- http://pypi.python.org/pypi/ClueReleaseManager

so now i have a few questions:
- is code behind pypi.python.org available and why i can't find some
up-to-date official document or howto for private pypi repository
(maybe it exists but i just can't find it)?
- since python is used in commercial environments i guess they
actually have private pypi repositories, where can i find docs that
defines what pypi is and how to implement it?
- can you recommend 1 option (software providing pypi like service)
that can be easily installed and configured as a service running on
apache2/mod_wsgi, has an active community and docs howto setup?
- i did found http://www.python.org/dev/peps/pep-0381/ - is this the
spec that above mentioned software is based upon?

any additional info or comments appreciated.

Aljosa Mohorovic