The overtime rules for the postseason aren't nearly as difficult as so many announcers and analysts want you to think they are. In fact, they are so simple that even Donovan McNabb could understand them.... well barring that he knew that games could actually go into overtime this time.
The playoffs feature a slightly different take on overtime than the preseason or regular season does. The first thing that makes sense when you think about it is that postseason games can't end in a tie. So no matter how many overtime periods the teams have to go through, the game keeps going until it ends.