I only have one thing to say NEVER!!! as in the above reply, ya you have the chance of the old wall paper comming loose. but you also will have the chance of the texture of the wall paper comming through the paint or else the pattern. either way it will look like some idiot who doesn't know what there doing did it. DO IT PROPERLY!!! strip the wall paper off using poly Stripper or steam. it will take a while but DO IT. then make shure you wash the walls very throughly using a product callde TSP. if you dont, once again you will have really poor results. When I bought my house the guy just pulled off the paper and painted. My walls look like crap! Now I have to coat all the walls from top to bottom with drywall mud and sand just to get the walls nice
So once againg do it right and peel off the wall paper