Sheldon Brown's Wheel Stuff. If you've ever loosened all the spoke nipples on a wheel, then tightened them back to get to a true wheel, you can do a wheel build. The part that precedes that is basically like putting a Lego set together. If you're not sure if you can do it, and have an old wheel, try it. For a first wheel build you will need a good spoke wrench, a truing stand, plus I recommend a spoke tension meter.

The Art of Wheelbuilding by Gerd Schraner is a good reference. I think you can find a pdf copy online.