On PhD/SoftWare I keep some documentation for getting software to do with my PhD to run.
I used virtualenv to set up a python environment in which I can install what I need and keep it separate from the main systems python and libraries. To activate it:
. ~thead/p/s/bin/activate # undo all changes, deactivate it just type deactivate
This will set your PATH and LD_LIBRARY_PATH to use python2.5.
Software installed in p/s/: