I just read an article in the NY Times about devices that translate one type of stimulus to another. For example, one of the devices translates visual input from a video camera to tactile stimulus on the user's tongue. And the user can "see", at least to some degree. Another guy who has no feeling in his hands was able to feel once again by using a special glove and some sort of stimulus device on his forehead.
What's especially interesting in the latter case is that the guy claims that the sensation was as though it was from his fingertips. On the BrainPort web site, there are some some video clips of a blind guy learning to use the video camera-tongue thing. His perceptions seem to be somewhere between mentally translating tactile sensations and "real" vision. This is a grown adult (who was able to see) learning to do this. I'd bet that a newborn baby with one of these things would be able to function very naturally in the world -- I'll have to restrict myself to talking about how people behave and report the sensation, because, not having experienced it, I have no idea how to talk about "what it's like."
I find this totally fascinating and tremendously relevant to philosophy of mind -- when I told my roommate Jonathan about this, he looked at me for a moment and then said, "I want to know what it's like to be a bat."