Development Tools

Hap Python Remote Debugger
A remote debugger and IDE that can also be used for local debugging.
http://hapdebugger.sourceforge.net/

IPython
An enhanced interactive Python shell with many features for object introspection, system shell access, and its own special command system for adding functionality when working interactively. [Open Source, LGPL]
http://ipython.scipy.org/

PyCrust - The Flakiest Python Shell
An interactive, graphical Python shell written in Python using wxPython.
http://sourceforge.net/projects/pycrust/

Pymerase
A tool intended to generate a python object model, relational database, and an object-relational model connecting the two using UML or XML. However, it has been extended to also output GUI widgets and can be easily extended to output whatever else you might like. [Open source, MIT License]
http://pymerase.sourceforge.net/

PyReverse
A set of tools for reverse engineering Python code, including creation of files readable by ArgoUML. Project information, downloads, and bug-track details. [Open Source, GPL]
http://www.logilab.org/2560/

Tixapps Applications Framework
Tixapps applications are a suite of development applications that run with Tk/Tcl or Python, using the Tix widget set. [Open Source, BSD-like]
http://tix.sourceforge.net/Tixapps/

Winpdb
An advanced python debugger, with support for smart breakpoints, multiple threads, namespace modification, embedded debugging and encrypted communication.
http://winpdb.org/