Generate virtualenv requirements.txt file with 'pip freeze'

Requirements file was generated with:

$ workon arthurcode
(switch to virtualenv)

(arthurcode) $ pip freeze > requirements.txt
settings.py: edited ADMINS, DATABASES, and TIME_ZONE

Initial database, timezone, and email-admin setting.  I'm using a
postgresql database with default credentials for
development.
Added psycopg2 to virtualenv

Regenerated requirements file with:
(arthurcode) $ pip freeze > requirements.txt
Added 'south' to list of INSTALLED_APS

I'm going to use South for database schema migrations.
The south app should be installed *before* syncdb is run for the first
time.
Customize the default admin page title & branding.

I wasn't able to find a way to do this without replacing the default
admin/base_site.html template.  Overriding specific blocks of
base_site.html didn't seem to work, and even the django tutorial
instructs us to replace this template.  I think that we can only use
template overriding to customize on a per app / per model basis.