I started watching the Pete Ramey DVD series on natural hoof trimming. It is excellent. I highly recommend this for anyone who is considering trimming their own horses, or just want to know how to give their horses' the best care possible, including nutrition, environment, movement, booting, trimming, etc. He trims a bunch of horses so that you can see over and over again what to do. I think it is invaluable for me. This information should really help me increase the performance of the horses I trim.
More information at : www.hoofrehab.com
His book is great too, if you haven't read it already.