The most recent release version as well as possible newer experimental versions are best found at the MacPython page maintained by Jack Jansen: http://homepages.cwi.nl/~jack/macpython.html.
Please refer to the README included with your distribution for the most up-to-date instructions.
Note that MacPython-OS9 runs fine on Mac OS X, and it runs in native mode, not in the Classic environment. Unless you have specific requirements for a CFM-based Python there is no reason not to use MacPython-OSX, though.