I think the biggest mistake people make when bringing up a foal (either filly or colt) is treating the foal like a big dog. I like to remind people "what is 'cute' now may not be so 'cute' when that horse is 1200lbs!" A horse must be taught respect asap. Not being mean, just who is the boss! That way, when he is over 1000lbs he still thinks of YOU as the boss and respects you.
I have raised many stallions. I will not raise a stallion who is over 1 yr old. I have found that they continue to respect you more as they get older and are easier to handle. Kinda like your parents. When you were little, they were BIG and you had to do what you were told. Now that you're big too, doesn't mean you don't listen to your parents. Know what I mean? To a foal, you are an adult member of the herd. If he learns respect from you then, it continues and they don't realize that they outweigh you by a ton!
If you want a colt vs a filly, that is fine. I would suggest that you geld him asap. That way, he doesn't learn what it is to be a man, and you have less problems later. According to my vet, you can geld them as soon as they are both dropped. (check with your own vet and what his/her practices are.) We have had them gelded as young as 3-4 months after they have been weaned.
The book recommended is a good book. Clinton Anderson also has some DVD's that may prove helpful. I would learn all I could about horsemanship in general before purchasing a horse. A foal and an adult is not that different IMO. Good luck and post pics when you get your new horse!