From Internet-Poker.co.uk - Iowa Online Poker Study Signed Into Law
Iowa is looking to see how an intrastate (Iowans playing other Iowans) online poker option will affect the state and its existing gambling enterprises. I think in general these intrastate attempts will fail (the possible exception would be the very densely populated states like California). Even a intra-country system where people in the US can only play other people in the US is a bad move in my opinion. What definitely works are sites where people from anywhere in the world can sit down and play poker against each other.
