We have the technology
Oscar Pistorius is a South-African athlete, world-record holder for the 100-, 200- and 400-meter races.
Oscar Pistorius has no legs, and runs on a pair of Cheetahs - carbon-fiber prosthetics attached at the knees, which led to his nickname of "Blade Runner". His current 100-meter world record is 10.91 seconds, compared to 9.74sec able-bodied world record. In 2007 Pistorius started competing in standard able-bodied competitions, but was hindered by new regulations preventing the use of "technical devices... [providing] an advantage over another athlete" - regulations that were overturned this month, paving the way for Pistorius to compete in the 2008 Summer Olympics - provided he makes the cut for the South African team. Incidentally, Ossur, the makers of the Cheetah, have a section on their website for Ossur Bionics - a division of the parent company does does in-bone implants and powered prosthetic limbs. A research division for the really cool stuff.
In another part of the world, Dean Kamen - inventor of the Segway - is working on prosthetic arms. His latest model - the Luke Arm, after everybody's favorite hand-chopped jedi - was demonstrated this week at the D6 technology conference.
These prosthetic limbs are amazingly cool - light, strong, flexible, and able to interface directly to nerve endings in the arms and shoulders. Though it's still far from having total natural control as with a natural limb, the Luke Arm responds directly to mentally impulses and provides feedback through a chest-mounted motor.
Apart from the obvious uses for amputees (the project was funded by DARPA, as part of a large-scale project of prosthetics for wounded soldiers), Kamen also has an exoskeleton version that can be worn on top of existing arms, used mostly for testing. The possibilities for this, of course, are endless. Doctor Octopus comes to mind immediately. Who wouldn't want the ability to graft an additional limb on top of our existing ones, whether to expand your reach, add specialized grips and connectors or anything else? Control would be a problem - the exoskeleton version doesn't jack into your nervous system, relying on manual controls or foot-pedals instead. But is there any reason why it couldn't be?
The videos from the D6 demonstration are quite impressive, showing remarkable control though the lack of fine-grained tactile and spatial feedback is apparent. Still, it's quite inspiring to see a man scratch his nose or pick up a grape with the exoskeleton. Later on, amputees pour drinks, raise spoons to mouths and pick up iron nails from an upturned palm. It's not Terminator, but it's not Captain Hook, either. It's cool, it's coming, and I - for one - welcome our new cyborg overlords.