Another thread on here asking about artificial insemination sparked me that we have no information on how to breed a horse. I found some quick and easy to follow instructions online.
How to Breed a Horse by eHow Pets Editor
Just reading through this, it almost seems easier than human breeding (for that almost perfect end product), as long as you take into consideration all the time spent prepping - maybe if we did that more with the human race, we would have a happier world, who knows?
Also: Read the Tips & Warnings section, it is a great little work of some key things to always remember!!