you can try partypoker or 888, generaly the big casinos. But to have succes you must have a comunity, like a blog about gambeling or a forum or maybe a website about a particular game like poker or roulette, they you can have a big succes with the affiliate of a casino.
Mainstreet affiliates has a 60% promo going on, accepting US players.
C-planet accepts canadian players. They are a good group as well.
Euro-partners and casinoblasters for european players.
Yes- target your game and build a site around it. Usually a strategy of some kind, which will draw your traffic, then if your lucky you can get some banner clicks. Also, AFIK, casino programs don't care if you stuff a cookie here or there.