Check out WebEcoist for some beautiful examples of green walls around the world and then G-Sky, a company that designs and installs green walls, for what's being done in the U.S.
The photo in this post is from TreeHugger; here's what they say about the wall's architect:
Patrick Blanc and Le Mur Végétal
But the reigning king of the living wall is Patrick Blanc. He invented a version that he calls Le Mur Végétal, or Plant Wall, a dense sheet of vegetation that can grow against any surface, or even in midair. It works by doing away entirely with dirt, instead growing plants hydroponically in felt pockets attached to a rigid plastic backing. His most famous is at the Quai Branley Museum; Read more at A Really Green Building: Quai Branley Office Wing