Originally Posted by MrFatbooty

That's your shutter speed. Those numbers are the length of time (in fractions of a second) the shutter is open and letting light from the lens shine on the camera's image sensor.

For this purpose you want to turn the dial on top to M for Manual.

Check the "resources" sticky in the photography/photoshop subforum for tutorial links 'n such.

Or you can hit me up on AIM some time and I can sort you out.