Position is basically your distance from the dealer button. The closer you are to the button the better your position is, therefore the big blind (and small blind if there is one) have the two worst positions. This disadvantage is partially offset by the fact that they have already partially or fully paid for the first bet pre-flop.
In the suggestions on Starting Hands you'll notice that you can play lower quality hands as you approach the dealer button, but be careful!
The worse your hand is at the beginning the harder you have to hit the flop to continue.
The advantage of position is an advantage of information. You get to see who bets and who checks (and who raises) before it is your turn to act. USE that information.