Check out this page for help with getting a room at discount.
http://www.mousesavers.com/disneyresorts.html
Another thing you could do is to rent timeshare points with Disney Vacation Club members. The points go for about $10 a piece and depending on when you go it could be a great deal. Look here for people buying and selling points:
http://www.disboards.com/forumdisplay.php?f=29
Look here for info on Disney Vacation Club
http://dvc.disney.go.com/dvc/index?bhcp=1
Look here for the charts that show how many points are needed to stay at the resorts:
http://www.dvcbyresale.com/PointsCharts.html