I am trying to use python in order to simulate social networks, this requires matplotlib.pyplot, networkx and xlrd. Everything works fine from terminal, IDLE or X11 but when I try to use TextMate import matplotlib.pyplot as plt and import xlrd throws up ImportError: No module named... however import networkx works fine! 
I downloaded python via EPD and so matplotlib came ready baked in however I got xlrd and networkx with easy_install. 
Anybody have an idea what might be going on?
You need to tell TextMate which Python to use.  One way to do that is to define the shell variable TM_PYTHON with an absolute path to the Python interpreter you want to use.  In the TextMate menu, select Preferences, then the Advanced tab, then the Shell Variables tab, and click + to add the new variable.  If you don't know the absolute path to the EPD Python, type which python (or whatever you are using to start Python) in a Terminal shell window.
Just downloaded TextMate, can't import modules