My personal favorite is
globexplorer.com except that a lot of the pictures are fairly old. For example, when I was trying to get some aerial Hydra pics, I took a look at Dorney (3830 Dorney Park Rd. and then panning) and Hercules was still standing but Talon was not. (Judging by the dirt/construction vehicles on site, it looked to be in the offseason when they were starting construction of Talon.) I don't know if they've updated their pics or not - I'm too lazy/tired to check right now - but that was in September '04.