http://www.gor-on-earth.com/
http://www.gor.net/encyclopedia.html

These will help you start off. I agree mostly with what has been said about the books, I got to then tenth one. But haven't really had the chance or need to go too much further. The books are rich with detail, but after reading him saying the exact damn thing so many times I got annoyed. But still a good read, so if you are really interested I suggest you try to find the first few an check them out.