I have updated the cookbook entry for yesterday to also include parallel processing for large data sets. Even if you're not interested in kd-trees, it is a good example of what the new multiprocessing standard module can do. There are still people being scared by the GIL, thinking it prevents Python from utilizing multicore processors.
http://www.scipy.org/Cookbook/KDTree -- http://mail.python.org/mailman/listinfo/python-list
