I am a complete beginner to Python/Django, but I want to dive right in and start experimenting. Thus I was following this guide on installing Python/Django http://devcenter.
Actually, if you use Ubuntu, it's just django-admin not django-admin.py.
django-admin
django-admin.py
Resides in /usr/bin Probably the same thing on Mac. You're using a Windows tutorial.
/usr/bin
It may also tell you
python manage.py runserver
and that is actually
python ./manage.py runserver