A good guide for people new to photography.

Exposure, Aperture and Shutter Speed.

Exposure is a combination of two fundamental camera settings – aperture diameter and shutter speed. Many combinations will give the right exposure, but each will have differences is depth of field, motion blur, and so on. This guide will teach you all you need to know so that you can get the right exposure and the right artisitic effect every time.

via Amateur Snapper | Exposure, Aperture and Shutter Speed Explained.