[jitter] Create a light sensitive camera switch

Hello all 

This is my first proper venture into electronics so I am only at a very basic level. I am trying to make a simple camera that is triggered when it sees light - or at least when a light dependant resistor sees light. Can someone tell me How do I do it? and what else I need? I can do it with a webcam (preferably one built inrto a mac) and arduino board (if nessesary) to show the concept.