Dealer - Self explanatory, its the one who is dealing the cards, or the one on "the button." This player has the advantage of position in the hand as he will be the last to act in a given betting round, except before the flop. So he can see what people are doing before making any decisions.
Small blind - this is the person first to the left of the dealer. He has half the blind, or minimum bet for the hand. He is in a bad position because he is first to act after the flop comes out.
Big blind - this is the person to the left of the small blind and is forced to put the minimum bet in the pot before even seeing cards. Now he has advantage of being last to act before the flop, so it is a good position to be in. He also has the advantage of being able to just do nothing if no one raises before the flop as well, so he can have a wider range of starting cards than most other players at the table. Usually if you are planning on raising before the flop, you want to raise it enough to make him not want to call just for the sake of protecting his forced bet.
So there you have it. I don't want to lay it all out right away, so I will follow up with future information later on down the road.