The following from
www.mousesavers.com might answer some of your questions
Annual Passholder rates for the Walt Disney World resort hotels are often the best discounts available -- up to 45% off. For the past several years, Annual Passholder rates have been available for most of the year, but Annual Passholder rates are NOT always offered and frequently are not offered during peak holiday periods.
The Disney World Annual Passholder rates are released seemingly at random. Walt Disney World now has an Annual Passholders section on its web site, where you can check for new offers -- but only if you already have a pass. If you don't have your pass yet, you can click here to see the current resort discounts. (Annual Passholders also receive meal, parking and merchandise discounts. Click here to see those.)
You may book up to three rooms at the Annual Passholder rates on one WDW Annual Pass. You do not need to have an Annual Pass at the time of booking your Walt Disney World resort room, but you must have it at check-in. It is my understanding that the Annual Pass must be in the same name as the person whose name appears on the reservation; a few people report that they bought a child's Annual Pass and used it successfully to get the room discount, but I wouldn't count on it.
If you buy a WDW Annual Pass in advance through the by phone at (407) W-DISNEY or online, you will receive a plastic card that is your "voucher" for an actual Annual Pass. The voucher must be "activated" (exchanged for the actual Annual Pass) at Guest Services outside of one of the Walt Disney World theme parks, or at the Guest Services Office in Downtown Disney. To activate the voucher, you'll have to show photo ID (for adults) and you'll get a finger scan that links your pass to you personally (which prevents sharing of the pass). Each time you enter the theme parks with the Annual Pass, you'll have to put two fingers in a scanner. If the scan fails, you'll be asked to show ID.
I don't see much point in purchasing the pass in advance, unless there's an imminent price increase and you want to buy the voucher before the price goes up, thus locking in the old price (and vouchers do not expire, by the way). In terms of convenience, you might as well wait and buy an actual Annual Pass when you arrive, because you're going to have to wait in line to get your voucher activated anyway.
