From DIYinfo.org
[edit] THE BASIC TOOLS YOU WILL NEED
If you want to hang wall coverings of any type successfully, it's worth investing in the proper tools for each stage of the job, they not only make life easier but the results are inevitably neater.
A folding table makes pasting and handling easy. Powder paste can be mixed up in any clean bucket, and is applied to the back of each length with a pasting brush or a large, clean paint brush. For smoothing the length onto the wall, a paper hanger's brush is used for most types; a sponge is better on washables and vinyl wall papers.
The first step in paperhanging is to ensure that each length is hung to a true vertical; it's no good using the room corners as a guide. The first length on each wall should be hung to a line marked with a plumb bob and straight edge (Right - a shaped weight attached to a length of string).
Once you've cut the first drop to the length you need, you can apply the paste. For this you need a folding pasting table, a bucket in which to mix and store the paste, and a pasting brush to apply it. Most wall coverings except washables and vinyl’s should be smoothed in place on the wall with a paperhanger's brush. This has a wide wooden handle and long, thick bristles which gently press the paper into angles and round obstacles without stretching or tearing it'. With washables and vinyl’s, a sponge can be used instead.
Trimming is best done with a pair of paperhanger's shears; the long blades make straight cuts easier to achieve. On some papers a proprietary wallpaper trimmer or a sharp handy man's knife plus a straight-edge can be used instead. A seam roller is a useful accessory for hanging smooth wall coverings; it helps to ensure that butt-jointed seams are firmly stuck to the wall.
For removing old wallpaper, a stiff flat-bladed scraper is the best tool to use, in conjunction with a hired steam stripping machine on painted or washable surfaces.