This -- it turns out -- comes with Python 2.6 installed.
It is, however, an incomplete build. To do anything, I had to install a some additional Python packages. Specifically, the "libraries and header files needed for Python development". Also, IIRC, the tkinter package isn't present by default.
Once I had the development package installed, I could add setuptools. After that, it's a sequence of easy_install steps and we were up and running.
I've started running our unit test suite with python -3 to capture all of the DeprecationWarnings. So far, there aren't many and they aren't show-stoppers. In one project we have some has_key methods and a use of urllib that needs to be replaced.
It's very, very nice to have a short, specific list of Python 3 compatibility issues to look out for. We're not going to use Python 3 any time soon, but it's nice to be able to solve the problems in advance.