See www.wxpython.org for the latest release, and search
the web for others.

wxPython is probably the 2nd most popular GUI toolkit
for Python, after Tkinter, and before PyQt.  In general,
it's more complex to code that Tkinter, but also more 
feature-rich.  PyQt sports roughly the same level of 
features and complexity, and is currently available in 
open source form from Nokia.  A fourth option, PyGTK 
seems to be in common use as well (see the web).