As a start, I first recommend this....
ThePhotoForum search page
Because I've posted three times in similar threads in the last 2 days.
Second, two links that I found hugely helpful when I bought my camera and was wondering about photography as opposed to snapshooting are as follows. They give a very good overview of the functions of a camera and the various modes and settings...
ShortCourses
Digicam Help
It is important to get a bit of a grasp of what all the A, S, M, P, auto modes are, whitebalance, metering, etc right off the bat.
Third,
Understanding Exposure has already been suggested. I just wanted to point out that I started with the links I posted above and was playing with shutter or aperture priority modes. Then I read the first 3 chapters of
Understanding Exposure and only the first 3 chapters so far. Just in those first 3 chapters, the info was enough for me to start getting more of a grasp of exposure and allowed me to easily move to using full manual mode on my camera.
Good luck. Check out those 2 links and the recommended book which is recommended nearly 4 times a day here

and it won't take you long to begin understanding. I only bought my camera right before Christmas. Previous to Christmas, I had a 7 year old 2 mp full auto (nothing manual) camera and was only taking horrible snapshots. That doesn't mean my photos are any better now, just that I'm capable of putting more thought into what I shoot with a camera over the standard random snapshooting I was doing previous.