The snail is of a fresh water variety. I know a majority of them are farm raised now.
here is what ol wikipedia had to say, it should help.
http://en.wikipedia.org/wiki/Escargot
For preperation, stick w/ the classics. Roasted with garlic and fresh parsley, and ALOT of butter,it is always a winner. Just don't over cook, or it will be like chewing a little rubber ball.