I think I found the company that makes the automatic music score device spotted on From the Top last night: MuseBook.
You can buy one online from Kelly's Music and Computers:
MuseBook Score is an electronic score solution which automatically turns page for you! Use a Tablet PC instead of sheet music and open MusicXML score files saved on your computer's hard disk. As you play the piano, MuseBook Score listens to the piano performance through a microphone, recognizes where you are playing, then turns pages automatically. MuseBook Score works with both acoustic and digital pianos.
Automatic Page Turning
Let MuseBook Score be your page turner. You concentrate only on the music, and then piano practicing becomes far more effective.
Current Position Display
Have MuseBook Score respond to your piano performance. As you play the piano, it indicates the current performing note with a color you defined. It provides not only an easier way of reading scores, but also more fun piano practicing by interactive learning environment.
With MuseBook Score, you can hear what the score sounds like. Listening to the score before you practice helps you understand and memorize the music better.
How does MuseBook Score work?
MuseBook Score listens to the live piano performance through a microphone connected to a computer and recognizes the complex performance utilizing artificial intelligence technology. Therefore, MuseBook Score automatically tracks current performing notes and turns the pages over when it is timed to.
Music recognition technology enables a machine or a computer to listen to the music and recognize its contents in a similar way as human ear and brain do. Artificial intelligence software emulates a human's music recognition process by means of digital signal processing.