Pysolar is a Python library for calculating the position of the sun relative to the earth as a function of latitude, longitude, and time. There is also code included for other problems related to the development of photovoltaic systems. Still in alpha.
Project moved to Google Code since SourceForce is a broken, buggy, non-responsive service. I had to re-log in over 100 times just to change this description. Please visit the project at http://code.google.com/p/starflighttlc/ for the latest version of th