See all the Building Skills videos at Fine Homebuilding:
http://www.finehomebuilding.com/blog/building-skills
In this episode, watch remodeler and Fine Homebuilding editor Justin Fink tape weather-lapped seams, and patch holes in new housewrap on an exterior wall. Getting these details right will keep water out, making your walls more durable. With taped seams, building paper can also work as an air barrier, helping insulation work better, and reducing condensation and mold-growth in your walls.
http://www.finehomebuilding.com/item/12985/building-skills-tape-housewrap-seams-to-keep-water-and-air-out