You need to download the utppd DMG file and mount it by double-clicking on it. Inside, you will find a MacOS X installer and installation instructions.
Installation should consist of clicking Continue and accepting the License Agreements, all of which are open source and so freely available for redistribution.
The most recent two releases of OS X, Mountain Lion (10.8) and Mavericks (10.9), no longer ship with support for one of the components assumed by our Python distribution. You will need to download and install the X11 Window system server, XQuartz, which is included in this directory for your convenience.
You can also visit the XQuartz Project Home to get other releases of the software (although there should be no need for you to do so).
Improvements in security for OSX 10.8 and 10.9 have resulted in a minor impediment to getting our Python distribution to install. The standard "double-click" to open will produce a warning dialog that says:
utppd-2012.1.mkpkg cannot be opened because it is from an unidentified developer
with the only option being to click OK and closing the window without installation.
This is easily worked around by using a "right-click" or "two-finger tap" to open the the action dialog. Selecting Open yields a similar warning window, but with the option to proceed by clicking on the Open button. At that point, you need only click on Continue to complete the installation.
The upgrade will delete an important folder with graphics libraries. To fix, re-install XQuartz.
If it still does not work, try installing the Python 2.7.3 distribution on top of the already installed UTPPD. This should not be necessary, but you may have accidentally blown away some other pieces of the distribution.