I went to the Colorado School of Trades a few years back. They have an excellent program, very hands on and self paced. I just think it is way over priced. It will give you a very good foundation to build on. The AGI stuff is great for reference material, and expanding your knowledge, but I would consider them more of a supplemental resource. The school gave me a good start, but apprenticing under a good smith has given me so much more than any school could. It has made getting started in this business so much easier for me having someone there who can answer my questions, or show me faster, better ways of accomplishing a task. Fair warning, you will work long frustrating hours, for very little money. My boss is fond of saying that anyone smart enough to be a gunsmith, is smart enough to do something else instead. I have watched a few people get into gunsmithing with lots of motivation, only to lose steam and go find something else to do after they realize how hard they have to work just to make a living. Only 2 or 3 of the people I went to the school with are actually working as a gunsmith 3 years later. However I find it to be very rewarding, from knowing that hundreds of people in my community are using guns I worked on to defend themselves and their families, or the excited hunting story about using grand-dad's old rifle that I accurized, which is shooting better than ever, and they are hunting with more confidence than before. I love my job, and take a great deal of pride in the services I provide to my community. The schools, books, correspondence courses are all valuable, but nothing beats an apprenticeship. If you can find a smith willing to take you on, save yourself the money and drink straight from the well. It will save you years of frustration to learn from the experience of someone who already has the t-shirts. Best of luck to ya, the world needs more gunsmiths. Semper Fi.
From what I have heard from smiths who attended them the Trinidad Community College program, and the Pennsylvania School are also excellent choices.