LiftPort Group Inc. has successfully tested a robot climber capable of climbing a ribbon attached to a weather balloon to an altitude of 1,000 ft. The group hopes to ascend to 1 mile before to long. The robot is just one component of the space elevator through. The other is the ribbon that it will climb, currently a fiberglass composite. The developers hope that there will be a carbon nanotube ribbon in the not to distant future.
In a related story NASA has announced a space elevator contest for engineers.
From Space.com: "In the $50,000 2005 Tether Challenge, teams will compete to make the strongest tether of a specified diameter. Tethers will be stretched until they break, and winners will advance in a March Madness-like bracket system. The winner must then beat NASA's "house tether," made of existing material, to snare the cash."