If you are a hobbyist (of aything - photography, guns, pets, fishing etc.) 10 - 15 years ago, the only way you'll information on your interest is by (physical) networking with your fellow local hobbyists, travelling the distance to someplace where there are more like-minded people or buying a crap-ton of magazines and printed resources available. Nowadays, you can still do all of that but thanks to the Internet, information is so much easier to come by.
Of course, nothing beats going out there and taking pictures of stuff and learning your craft and your gear by experience. But, and this is a big but, it wouldn't hurt to have some info on hand before you go out. I've proven that when I took pictures of fireworks last Christmas day. The display lasted only minutes, there is no time to experiment at the spot for those kinds of occasion.
Having said that, here are a few useful guides you can check online to learn your Canon EOS 500D DSLR camera.
First is YouTube user rickjbradbury.
He has some pretty useful videos to get you more familiar with your camera. Most of them are also mentioned on the manual but if you're the type of person who doesn't want to read the manual and wants a more stimulating learning method, check out his videos. He also answers questions and comments. Really nice guy.
Another one is this online guide from Canon.
This guide is applicable to all Canon DSLR cameras and not just the EOS 500D. It also has some basic photography concepts. If you have a point-and-shoot camera with manual controls, you can also refer to this guide.
There are also tons of forums where you can ask questions from seasoned photographers and beginners as well. But if you ask me, the first thing you should always do is read the manual! The Internet is full of rude people and some will give you an answer like RTFM (read the f****** manual) and they have a point. Before asking for help, help yourself first.