Ahhh...DSLR newbie then.
Ooops...I meant John Hedgecoe for the books. John Shaw has some very nice ones as well, but more geared toward landscape shooting. Hedgecoe's are mini photography courses.
Any ISO higher than 800 on the newest DSLRs starts to get a little noisy. You can do some creative levels adjustments to correct a lot of it though.
Best advice...take it out of full auto mode and use the meter readouts in the viewfinder to learn the ins and outs of manual exposure. The standard exposure settings for front-lit subjects in full sunlight are: f/16 at the nearest reciprocal of the ISO setting. Example:
ISO 100
f/16 at 1/125
That's a basic starting point. When you change the f-stop, the meters will guide you as to the proper way to change the shutter speed. Examples:
ISO 100
f/22 at 1/60
f/16 at 1/125
f/11 at 1/250
f/8 at 1/500
I usually try not to shoot above an ISO of 400...ISO 800 is OK if I can get away with shooting without a monopod/tripod. If not, and the shutter speed gets below the ISO, it's flash all the way.
Just a few quick tips for all.
C