I have the Platinum Pass (have had it for years). Purchased at Orlando, so it was more expensive than the other sites. But they've never raised the rates on me (I pay monthly) so I think it's a bargain compared to the current rates. It doesn't include Aquatica though, since I first bought the pass before Aquatica was built.
Anyway, I get free preferred parking at Seaworld Orlando, Busch Gardens Tampa, and Busch Gardens Williamsburg. I get free regular parking at Seaworld San Antonio and Seaworld San Diego.
If you are talking about the 1yr or 2yr pass for the Florida parks, then you and choose 1, 2, 3, or 4 parks (Choosing from Seaworld Orlando, Aquatica, Busch Gardens Tampa, and Adventure Island), and you get free general parking at the parks you've chosen. Price depends on how many parks you choose.