Note that the official version of Python for this course is Python 3.4. You will probably be able to get away with using 3.3, but you should NOT use Python 2.
Python programs are plain-text files, so you can use any text editor you like. However, Python-aware editors have features like syntax-coloring and auto-completion that will make your life easier. The following editors are all reasonable choices. If you don't like any of these options, the Python wiki contains a large list of Python editors and IDE's.
Cross Platform:
IDLE | This is the "official" Python editor. It is ugly and clunky but functional. Since it usually ships with Python, no extra installation is required. |
Eclipse with PyDev | This seems to be the most polished and complete open-source development environment for Python. It includes integrated unit-testing, a graphical debugger, and code-completion. |
Aptana Studio | This is basically a re-branded version of Eclipse designed for web development. It ships with PyDev pre-installed, so it might be easier to get running than Eclipse. |
Windows:
Notepad++ | Make sure to configure this to insert spaces instead of tabs! |
OS X:
TextWrangler | Make sure to configure this to insert spaces instead of tabs! |