Canada and European countries have allowed production of industrial grade hemp, which isn't potent enough to get anyone high.
It's illegal to produce, but not possess hemp in the United States, so American companies have to import it from Canada or elsewhere.
It's uses range from building materials (composite wood board replacements, hempcrete, insulation, stucco, etc) to vitamin rich food products, car interiors, etc.
The USDA said it best: http://www.youtube.com/watch?v=jokV8xlJTNE
Please educate yourself, as a building material hempcrete is carbon negative, taking more carbon out of the environment than it took to produce. It grows in places unsuitable to other types of farming, it restores soil nutrients with it's deep root system, is rot resistent, pest resistent, non toxic.