There is a luck and a skill side to poker. The luck side keeps the bad players in with their occasional wins, thinking they are good at poker or are overall winners, while the skill side wins money in the long run. The effect of having good or bad cards dealt is described as variance, if you look at a winning poker players profit/loss graph it will be a bumpy road upwards. The individual bumps are short term variance, the overall trend reflects the skill of the player.
How can skill count ? What if you have a middle pair, youre opponent has top pair, and he bets the river. You raise...because you know he's a player that can fold a top pair type hand based on his previous play, and based on your tight image, and based on the cards on the table. He folds the better hand. So its not JUST luck, its strategy and perception of your own image and your opponents playing tendencies.
Skill is also about extracting the maximum amount of value out of your better hands, and FOLDING when you know youre beat.
If you want to read some real poker strategy go to a poker strategy site and browse the theory articles, judging by the discussion here a lot of you will be surprised at the amount of strategy in the game.
And just to answer a previous post by someone, yea phil ivey is (one of) the best poker players, but tournaments are extremly high variance - you need to play a lot of them before you can judge if you are a winning player or not. Cash games are lower variance generally.