For an entry level (d)SLR I would stick with Canon, either the 1000D or 450D. They're the best bang for your buck and they're very popular, thus you have a lot of options for upgrades and attachments. This also means you'll be able to borrow a lot of of equipment to experiment with from photography friends since they most likely use Canons too.
If you buy a kit, you'll need to buy a decent lens because I've never been happy with the kit lenses. Since you're on a budget, go with the Canon EF 50mm f/1.8 II lens. It's the best overall lens out there for anyone who doesn't want to spend some serious $$$. It's versatile and performs surprisingly well.
Once you start getting the hang of everything and you're ready to throw some more $$$ at it, you'll also want to invest in some glass, because that usually matters more than the camera body itself. Most people use this for a rule of thumb: take your budget, divide it into thirds, spend 1/3 on the body and the other 2/3s on lenses.
Oh, and check out B&H used store for some good deals (not an affiliate link):
Code:
http://www.bhphotovideo.com/c/buy/SLR-Digital-Cameras/ci/15488/N/4294182649
My apologies if I told you anything you already know, just wanted to get you started in the right direction.