BrainPort lets you see with your tongue, might actually make it to market
http://www.engadget.com/2009/08/14/brainport-lets-you-see-with-your-tongue-might-actually-make-it
"the device translates signals from a head-mounted camera to electrical pulses that lightly zap your tongue in response to visual stimuli -- early results have shown people can regain a good bit of their spatial awareness and even read large writing."