I really think you can learn it yourself if you are motivated and handy. My approach was to buy the BBI manuals, buy a bunch of "grab-bag" bike stuff on ebay, and then experiment with everything. It was probably a lot cheaper than bike mechanics school. And if you're not motivated and not handy, I doubt the school will help much.
I took the same approach when I used to build golf clubs. Eventually I could have taught most of those club-building classes.