My main advice would be to keep Corn Snakes for a few years before jumping into breeding.
First off, find out if you can sell them where you live. The Corn Snake market has slowed down with the Credit Crunch and if you can't sell locally, you could find yourself with lots of hungry mouths to feed.
Secondly, save up some money so that you can buy the right hatchling setups. You'll spend more money than you make in year one. Breeding can be an expensive undertaking.
Female Corn Snakes should be mated when they are a minimum of three years old, 300g in weight and three feet long. If they breed when younger or smaller, you risk complications.
Breeding season is February to about now.
Buy the book called "Corns Snakes: The Comprehensive Owner's Guide" by Bill and Kathy Love. That not only contains all you need to know about Corn Snake husbandry when starting out, but also the detail you need on how to breed.