Alton Towers: March 17th
Thorpe Park: Currently OPEN until 18th, then re-opens on 24th and closes again on 25th then on and off throughout March, until the official opening date for the 2007 season: March 17th!
Flamingoland: 24th March

Those are the main themeparks, for anything other see their websites

Florida parks:
Universal Resort: Open
Seaworld: Open
Disney Parks: Open
Busch Gardens: Open

Come on Tussauds, sure you can do that aswell?