First - call and book NOW! Just tried pricing 2 adults for Pop Century for Dec 26-30, 2005 on disneyworld.com and the first thing showing up was CSR Suites!
Second, Holiday season is Dec 20-31, and there are usually no discounts during that time, even AAA. It is also the highest priced resort season. (You may have a slim chance to get AAA rates before the 25th, but I doubt after)
Good Luck!
Michael