http://www.learnkoreanlp.com/2006/11/hi-newcomers.html ^^ this is helpful too, and it's free. :p

There's a few levels of formality in Korean. I think maybe there's like 6 levels? But two of those are archaic and not used anymore. There are four levels that I've been working with and as far as conjugation goes there's about six different ways that verbs and adjectives end and depending on that, that tells you how you will conjugate. How to conjugate into the different formalities is the next thing. There's a book I just bought called 500 basic Korean verbs, by Kyubyong Park. He has another book I bought, mastering conversational Korean. He explains the concepts really well, in my opinion. The verb book is really helpful too. You find the word you want or a word that has the same ending and it has all the possible ways for it to be conjugated in the varying formalities, tenses, and some other things. ^^ you should take a look at it.