From site: The SimCam is an online camera simulator designed to teach basic photographic principles. Whether you are interested in film or digital photography, the concepts are the same.
Shutter and Aperture
Basic f-stop and shutter – Adjust the camera settings and examine the results to understand the relationship between shutter and aperture.
Film Speed
Learn about film speed – Shoot the same scene with two differant film speeds and compare exposures side by side.
Camera Shake
Learn how to spot and avoid camera-shake – Compare wide-angle and zoom examples side by side.