NetworkX and Plazes
NetworkX is "a Python package for the creation, manipulation, and study of the structure, dynamics, and functions of complex networks." I've been doing some experimenting with NetworkX as a tool for rendering Plazes friend relationships graphically as a follow-on to some preliminary work I did using NodeBox.
All of what is described here assumes you're running Mac OS X Leopard; if not, much of what I describe is still possible, but the procedures will need tweaking.
To install NetworkX is easy:
This should do everything you need, and when the install process is completed with "Finished processing dependencies for networkx" you are set.
Installing matplotlib, using for drawing graphs, is similarly easy: