There are several ways of removing wallpaper. First, you must know what surface you are working with. Steamers which can be rented have always been my favorite especially for plaster walls. You merely steam the paper and scrape off. I have also used several stripping products, which you can find at your local paint and wallpaper stores.
There is a tool that you may use along with the strippers, which scores the paper for removal, these are best used with pretty solid under layers. If the wallboard was not prepared well before papering you may find that these tools may score your actual wallboard, which is something you don't want.
If the paper has been put up on well prepared walls or plaster I have even used vinegar and water.