Thought people might be interested in this.
http://www.goko.com/games
It is in Beta, but there are a few good games slated to come out for it, including Race for the Galaxy, Settlers of America and a couple Catan games.
Right now, there is Dominion, plus a couple other games. It is the F2P model, where you can play the basic game for free but can purchase expansions. There is single player, a campaign mode and multi-player lobbies where you can start games.