If you’re not sure of what Chaos magic is, chaosmatrix.org is a good place to start; spiralnature.com also has a nice selection of essays. Basically, no, chaos magic isn’t about being all evil and scary, or about Tiamat-worship, and it’s not the same as Discordianism. In this case, Chaos hails back to the original Greek definition of the term, the vast void that contains all potential for reality. Chaos magic is, in part, about tapping into this potential (though not necessarily in a literal manner). Check the links above for a more thorough overview.
This particular system gave me both good and bad influences. On the good side, it made my approach to magic a lot more flexible. I wouldn’t have done nearly as much experimentation with magic as I had without it, and I also probably would have a much more dogmatic approach than I do now. However, one of the negative effects is that for a while it shoved me almost purely into a psychological view of magic, in which deities and spirits were merely figments of my psyche. (Not that Chaos magic will do this to everyone, of course). I have since gotten over such a solipsistic viewpoint and am much happier for it.