The site that I've used in the past is scoresandodds.com.
You can always use vegasinsider.com as well, but their openers don't always seem accurate on the main odds page. On vegasinsider though, if you click on one of the lines for a game, it will direct you to each Vegas casinos' openers and line movement on the game.
There is always the ODDS link at the top of CTG as well. I haven't ever used it, and I'm not even sure it really ever worked, but I just checked it out after you brought this up and it seems pretty good. Has the opener on the left, and then 7 offshore books' odds on the game. Would like to know where the opener is from, as well as the % that is listed for each game.