They changed the ticketing, if I remember correctly. You can buy an all-club pass, or passes for single clubs. I think they changed it when they decided to let people walk through PI instead of around. Although I have to admit that there's nothing more disconcerting than coming out of a club at about 1am and running into a family with several small children wandering around PI.
I agree with Syrreal. I'm not a fan of the Beach Club, but I love 8-Trax and Mannequins. Can't wait to go in March!