There are also various blacklists online. There is one here, check it out! There's also Daves ESL and Marks ESL amongst many others.
Research research research and get things in writing, via email, before you get there. I've seen many horror stories about teachers in Korea being "zapped" by real ratbags and being left high and dry. To be fair to Korea though, there are horror stories about every country people teach in so passing judgement would be erroneous.
Just do your research man, and be sure of the facts before you leap in.
All the other tips by cool ice are good too, concerning funds etc.
Good luck and take care!
My 2 cents said.
