So this is something that we want to get into fairly soon, and its talking about the basic aspects of your camera, including both SLR and Point and Shoot style cameras, but until we do, here’s a nice article in regards to your cameras ISO control.
Here’s a brief snippet …
ISO in a nutshell
I get a lot of questions about ISO—many photographers don’t seem to understand exactly what it does. Your camera’s ISO control determines how sensitive the camera’s sensor is to light. On most cameras, ISO starts at 100 and goes up from there; the higher the number, the more sensitive the sensor will be.