I have been playing with the idea of getting a flash for my Canon. I wanted to see if anyone had thoughts on the subject or had a great forum that they could point me to.
can't recommend any particular flashes, but if you're looking for tutorials and some reviews i recommend checking out http://strobist.blogspot.co.uk
The Strobist is awesome, best non-dead-tree resource I've ever read concerning how to use flash properly.
As for what kind of flash to buy, you absolutely cannot go wrong with the Speedlight 430EX II. When you're first starting out with flash photography $250 seems like a lot of money for a glorified light bulb, but it has all the features you'll ever need as a hobbyist photographer and will grow along with your skill level. By that I mean it can shoot in fully automatic TTL metered mode where all you have to do is point and shoot, or it can be dialed in completely manually. It's an awesome flash and worth the price tag.