Here are some sites I have found invaluable in my search to find out information about teaching English overseas:
http://middlekingdomlife.com/guide/ - Great site dealing with aspects of getting to and living in China.
http://raoulschinasaloon.com/ - Objective, ad-free forums about teaching in China.
ttp://www.nap.edu/catalog.php?record_id=2111#toc - A book, China Bound, Revised: A Guide to Academic Life and Work in the PRC. Though this book was written in 1994 it has a lot of information that could still be relevant. The site itself might present opportunities with other books as well--you can read this one online for free.
http://www.couchsurfing.org/home.html - Some of the most useful information I have mined so far has come from people on this site. Couchsurfing is travel site that helps you find people to meet and places to crash wherever you are in the world. I plugged in various locations in China that I'm interested in and just started sending messages to people who teach or live there.
http://www.abebooks.com/ - A great site to buy cheap books from.