Arbormaster is good training. Its expencive but good. I would look into some reading before you get into anything like that though. Jeff Jepson's "Tree Climbers Companion" is good. Anything by Alex Shigo is normally a good read for the biology side of the trees (very important). North American Training Solutions does classes too. Not quite as expencive as Arbormaster and more flexible with what they teach. Get with a Professional in your area. Work with them for a while. On the job training is the easiest way to learn and you get paid to do it.