I started detailing about 3-4 years ago, pretty much right after I got my E46. It's not that hard to do, but it's not easy or cheap to do either. If you invest the right amount of time in both practice and research, you can do a very good job. If you have issues with paint overspray, required wet sanding, etc then consult a pro. If you have some swirls and scratches, it's totally possibly to DIY.
To the guy who said $50 for the whole kit, you are insane. I have a jar of wax alone that costs $50. My detailing kit right now is probably valued at ~$500+ and I have a very basic one. I detail on the side and do my own and my family's cars but that's about it. I find it soothing and relaxing to do the work myself.
For the people who want to try it out, get a quality dual action polisher and some light compound/pad, Meguiar's 205 with black pad, and have at it. You won't and can't damage the paint with this combination. Doing this gives you an idea of the right techniques and hand motions required to do a good job without chances of damaging your car. Also, read, read, read, and then read some more. That's the best way to learn.