It would be nice if a Python 3.3 package existed for OS X.
I figured out how to build it from binary.
All you need on Mountain Lion is a current XCode and the accompanying command line tools, GNU Fortran from R's website's tools section, numpy and scipy (I think) and you're gold! (kind of convoluted, but it worked :D).
I'm having a hard time building it with 3.3 and 10.7:
a few errors with numpy after running unit tests: http://pastebin.com/5XF0qAe5
massive errors with matplotlib: http://pastebin.com/fh6YZpTH
I have gfortran installed (I think I did that) and compiled numpy with that. Does anyone know why I would get so many errors with matplotlib?