I use pinnacle and a couple local bookies, but pinnacle doesn't let you bet if you're from America.
http://www.thegreek.com/
www.betjamaica.com
http://www.wsex.com/
http://www.sportsbook.com/
those are some decent online books
make an account at a bunch of books, look around for the best odds.
If you're not in the states I recommend Pinnacle, I've found them to have the best odds most of the time.