Unfortunately, it seems the official documentation on installing Python modules[0] makes absolutely no mention of pip or even easy_install. Seems like something that should be there, right?
I guess that is because pip is not part of the official Python. Maybe best described as a front-end to distutils (which is what your link documents and is part of official Python).
edit: Python docs front-page[1] also notes following:
A new documentation project, which will be merged into the Python documentation soon, covers creating, installing and distributing Python packages: http://guide.python-distribute.org/
[0]: http://docs.python.org/install/