I've been taking pictures with a DSLR for quite a few years now and the best advice I can give is to concentrate on the basics first. Turn off all the automation and learn how to shoot manual. Then, when you understand aperture, shutter speed, focal length, ISO, spot metering etc. you can study the manual and try to figure out if any of the more automated features still make any sense to you. (To me they don't. I always use spot metering and shoot in either "aperture priority" or "manual" with ISO manually set).
Shooting good-looking images with flash is surprisingly hard. A friend of mine who went down that route and spent the better part of a year learning shooting with flash recommended this book:
Also, you should learn how to use Lightroom, Aperture, Bibble or similar for post processing. (If you understand how the postprocessing tools work you can shoot with that in mind).
But most important: shoot every day. Practice as often as you can. Bring your camera with you everywhere. If you shoot a few thousand frames per month for a year you are bound to learn something.
That's a good example of how to become a good photographer in just a year. (If you click through his photo stream you'll find a lot of interesting images that were shot with flash).
Flash in photography is a tool like any other. It can be used well or used poorly. After discovering the strobist blog a few years ago, I found that controlling light with flash and lighting in layers has opened up a bunch of new creative opportunities for me.
I strongly suggest checking it out if you're a serious photographer. Http://strobist.blogspot.com
And contrast. And totally screws with lighting depth. And red-eye.
Assuming built-in flash alligned with the camera lens. You can mitigate a lot of this with bounce and slave units. Still, I'm finding that natural lighting and a small tripod (even a 6" mini braceable on a wall or pole) does wonders and makes for some stunning photos. At other times, even motion blur can be useful (especially for night/club shots).