Yes, you can book the AP rates without actually having passes in hand. The new rates that just came out use code EWP. As long as you have the passes when you check in, you'll be fine.
AP rates seem to be the best out there, along with email or postcard rates that only target certain people. If you know when you're going, book now! There are a limited number of AP rooms, and there is the very real possibility of them selling out.
Doug