the absolute best way to get wallpaper off is to steam it off with a wallpaper steamer. I've tried every other way there is, warm water, paper tigers etc, and after I bought the steamer it comes off like sliced butter everytime with very little damage to the drywall behind it. It makes a mess so have plenty of towels/mop bucket around to dry the walls afterwards. they run around 40 bucks at home depot and even if your only doin this one time, its worth every penny.
http://www.homedepot.com/webapp/wcs/...4X-_-100532752