it's probably the second most common one. careful though, angelfire walks a fine line, so don't stray too far into the site unless you're into satanism.
you should learn the basics of magick first, so you can be safe because you'll be working with astral beings. while they're not evil, they can attack you if you don't know what you're doing. so be sure you know protection, circle casting, meditation and astral projection. [since dragons live on the astral, it's easier to go to them]
if you're looking for books, the only one you can buy from a store is probably by D.J. Conway [Dancing with Dragons and Mystical Dragon Magic] but take her work with a grain of salt as a lot of it is false. the only thing i found helpful in those books was her guided meditation. there's a few books you can buy on amazon that are apparently good, but i've never read them so i can't give you a yes or no.
while studying from others is ok, you should learn under the dragons, this path is more spiritual based, and each person has different experiences. if you're planing on studying Dragon Magick because it sounds cool, or powerful, you're in for a rude awakening. i wish you luck, but be sure you're doing it for the right reasons.