I also recommend Pete Ramey's book. Its a great start to understanding the hoof, and an easy read. I started with that book. I carried it under my arm for 2 weeks and read it 5 times. It's exactly what you need to get started with the barefoot trim. I've got his latest book now. Been under my arm for a month and am on my 2nd run with it.
You know why I like Pete Ramey? Because he doesn't think he's the guru of horse feets. He makes mistakes and he learns from them and shares that. He's not so full of himself that questions bother him. Most of all he makes sense. Its gotta make sense!
The best case scenario is to call in barefoot trimmer and learn with hoof in hand. He should let you and show you how to maintain the trim in between his visits. Soon, you'll be able to it yourself. Best way to learn....with a professional and hoof in hand. This is for your own personal horses. If you tend to hang up a shingle, that's a whole nuther ball of wax...clinics, school, books,certification, dissections, reading rads, nutrition etc.