PyDev is a very good and popular Python IDE plug-in for Eclipse SDE. Adding it to Eclipse is straight forward: just follow "Quick Install" in the download page or detailed instructions from Installation section of PyDev manual.
I chose the installation via Update Manager:
Start Eclipse and set up Python Interpreters in menu Windows/Preferences:
by clicking "Auto Config" or "New..." button.
For testing create a new Pydev project from menu File/New/Project:
Write any simple code and run:
Python extension module Psyco can be installed in order to speed up debugging. It's a pity I could not make it work with Python 2.6 - it shows the warning that "psyco is not available...":
It works fine with Python 2.5: