Yup, like Neal said...do not house 2 snakes together. It is very stressful for them.
As far as tank size, there are varying opinions on this, but I'd say a 30 gal, one for each snake if you get 2. Definitely make sure you read up on the proper care and maintenance so you know everything you have to do to keep them healthy and happy (we have an excellent care sheet here http://ball-pythons.net/modules/Sect...warticle&id=59).
As far as breeding, females have to be pretty large (around 1200 grams) before they are considered breeding size. As far as I know, most breeders wait til the snake is around 2 to 3 years old before they try breeding it...although I guess males can be ready a little earlier than that. Feel free to correct me if I'm wrong
But, like another poster said, if you're only getting into it for the money then maybe you should reconsider. You have to really care about your snakes and be willing to put the time and effort (and money) in to do it right![]()