Here's a nice little video from Mike Sexton, the voice of the WPT, explaining why poker is a game of skill. Obviously I agree with this concept, but I like the way he puts it.
As Mike explains here, if there is anyone who thinks that poker is NOT a game of skill, let's setup a game every other week and we'll see who comes out the winner at the end of the year. I'll be taking all your money, which is why playing poker is clearly a game of skill.