Jay's suggestion to prime and seal the wall first MIGHT work, if you use a pigmented shellac like BIN or oil based primer or enamel undercoater. It will not, however, solve the issue of an unsightly finish due to the glue that remains. The solution is to thoroughly remove the glue, prime the wall, and paint. Get a gallon of DIF wallpaper paste remover, available at any home center. You will want to do one wall at a time and use plenty of drop cloths. Using a pump-type garden sprayer and HOT water, soak the wall and you will see the glue raise. Now add the DIF to the sprayer, a little more concentrated than is recommended on the bottle. Spray the walls again, making sure the solution is HOT. After 5-10 minutes, you will easily be able to wipe off the glue with a wet sponge. For stubborn areas, use a wide blade paint scraper, but be careful not to gouge the walls. Keep a large bucket of fresh water handy or rinse the sponge often to remove any residue. You may need to apply more DIF if the first application doesn't take it all off. Finally, spray some more fresh water, wipe completely, and let dry. Turn the heat up and/or open the windows and/or use fans to assist with the drying. After drying 24-48 hours, you can then spackle as necessary, prime the entire wall, and paint as usual. This is a messy job, so I advise others who are contemplating removing wallpaper to be diligent in getting the paste off before painting. Best of Luck.