If there is no Arduino then the application is quite simple. Your PIR is going to produce a high voltage out when motion is detected. The output voltage from the PIR can just connect to the base of an NPN transitor. Which will then open the transistor to the emitter which you would have your buzzer connected to. Here is a rough schematic. http://picasaweb.google.com/lh/photo/o3Q7wgP009NKe7nlSZxipz2qwst-Qvyrn_-T3i-6zWM?feat=directlink. I don't see why that shouldn't work. Anyone disagree? You are going to have to play with the resistor values.