Python Mode is a major editing mode for the EmacsEditor. It is part of the source distribution of Python (as the file Misc/python-mode.el).
The EmacsWiki page for PythonMode has information on how to install, configure and add shortcuts keys to python-mode.
The [http://www.python.org/emacs/python-mode/python-mode.el current release] is version 4.6 (~123KB). The list of changes since the last released version [http://www.python.org/emacs/python-mode/changes-406.html are given in detail], as well as some [http://www.python.org/emacs/python-mode/installation.html installation notes.] If you're having problems with font-lock in python-mode, read the [http://www.python.org/emacs/python-mode/faq.html FAQ.]