The file C:\Python24\Lib\sitecustomize.py (which I think doesn't exist by default) executes every time Python starts. (This means not just your IDLE session but every time you run any Python script.)
One use for this file is to invoke sys.setdefaultencoding because that name gets deleted during initialization and so is unavailable by the time your main script starts executing. You can also put in any other code, such as "from btools import *". You can also put your btools.py file in C:\Python24\Lib\site-packages folder and it will be available from any program (as opposed to requiring it in the current directory). -- http://mail.python.org/mailman/listinfo/python-list
