How to add to the PYTHONPATH in Windows, so it finds my modules/packages?
This PYTHONPATH variable needs to be set for ArcPY when ArcGIS Desktop is installed. 
PYTHONPATH=C:\arcgis\bin (your ArcGIS home bin)
For some reason it never was set when I used the installer on a Windows 7 32-bit system.
I have a directory which hosts all of my Django apps (C:\My_Projects). I want to add this directory to my PYTHONPATH so I can call the apps directly.
I tried adding C:\My_Projects\; to my Windows Path variable from the Windows GUI (My Computer > Properties > Advanced System Settings > Environment Variables). But it still doesn't read the coltrane module and generates this error:

Error: No module named coltrane