How do you train a Siberian husky to pull a sled?

I'm interested in owning a Siberian husky and going 'sled racing' every year, but I want to know some things before I get myself into it. Well I do know that you have to start when there young and work the weight up as they get older, and about the harnesses and sleds, but I don't completely know how much work it will be. I want to know how hard the training will be. Also what commands should I use? I know mush, gee and haw. That's it though.