First, I believe the codes are out through April only right now. I made a reservation last night for August and the CM told me to watch for updated codes, but wouldn't tell me when they were coming out.
How much you will save depends. We used the AP discount on the AKL and Poly in May 2004 and saved about 25%. But the savings vary from year to year and depending on the season (value, regular, peak).
As far as how it works, just call like mad when they release the codes for your dates. They will apply the AP discount to your existing reservation if it is available. Don't be discouraged if it is not immediately available for your resort or room type. When they released the codes for May 2004, the first time I called I got the AP rate for the AKL, but not the Poly. I called back every couple of days and eventually I was able to get it for the Poly too.
Good luck.
