I just jacked it up, took the wheel off, and had at it. It really doesn't take that long. It took me probaly 1-2 hours for all four. If you get the high heat spray paint, I would suggest spraying into a glass jar or something and painting out of that. You won't have to mask or worry about overspray, and you can get more detailed with a small brush, Q-Tips, etc...
I did it mostly to get rid of that rust-like staining that started happening the moment I brought the car home. I got some 400 grit sand paper and sanded the outside of the disk, the center of the disk (don't sand the rotor surface where the brakes make contact), and as much of the caliper that I could reach. then cleaned everything off and painted. The end result looks a lot cleaner and in a nice subtle mod. I didn't want my factory brakes to stand out, so I chose silver, since both my car and wheels are silver. I doubt anybody except thost that I have told would even notice they were painted. However before they were painted, everybody noticed the rust.