Jon - my laptop does that. I thought: How neat!
I used it once and then never again. I don't know why...I think I can type faster than I can dictate.
It's Windows Vista. I don't know if all Vista packages do it. But you can tell it open window, close window, dictate to it, etc. That technology still seems sluggy. I can't wait for the Star Trek: TNG computers to come out, where you can just talk to it and don't have to repeat things or correct the mistakes the computer makes.
How about a thought-keyboard? Hmmm...I don't know, maybe not. I don't know if some of my thoughts would look very nice on paper.