Hi, AP newbies...
I have just been "converted" to being an AP holder after reading these boards (and a couple of other discussion boards as well).
I bought my AP online through the WDW website. I wasn't going to *count on it* for a room discount...I knew that I was going to WDW twice this year, so it was going to pay for itself just by virtue of not buying 2 4-day parkhoppers (one for each trip). You with me so far?
You can also get the AP at your local
Disney store, if you have one. What I got from ordering the AP online was a little card that looks like a park hopper-type ticket, but it said "voucher" on it. I did not activate it until I arrived at WDW, and even then, I actually activated it the day after I arrived (since our plane didn't land until 10:30 pm). You can just activate it at the entrance to whichever park you visit first, or at TTC (main ticket area). The AP is good for 1 year from the date of activation.
When I made the room reservations...I had first reserved at regular rates, as the AP rate had not been released. And then I watched this discussion board carefully. When someone posted that AP rates for the dates I was going, and said they were (finally) available, I called WDW and changed my existing reservation to reflect the AP rates. I didn't call at 7 am, nor was I too concerned about them running out of rooms at that rate. However, this is maybe where I differ in vacation planning from some other people on the board. I knew I'd be staying at the Poly, no matter what, and was in a position to pay rack rate if necessary. I think some people use the AP to upgrade to rooms that might otherwise strain their budget, which is great for them...I'm all for saving money, but still getting a nicer room!!
If you KNOW you will be using the AP for park entry, and that it is going to be a savings for you, even without a room discount, then you can buy it at anytime. If you are buying it strictly for the room discount idea, then I would wait until AP rates are released for when you are going. Does that make sense? See mousesavers.com for a discussion on when you "break even" by buying an AP.
I have saved a bundle with mine, by the way. Just on the first trip (5 nights at the Poly), with the savings on the room, I saved enough to cover the cost of the AP. And now I have booked another quick trip, and saved another $60/night at POR, not to mention I don't have to buy parkhoppers all year.
Hope this helps...I know it's long, but having just been through the learning process myself, I was hoping to "walk you through it" a little more.
cheers!