Finding Digital Scans of Sheet Music?
Crymson asks: "I've been trying to find a repository of sheet music out on the web. I'm mostly interested in Classical, although scores for Brass pieces would be nice. I'm sure with Google digitizing all the books of the world, someone must be digitizing all of the sheet music. I don't want special viewers, and I don't want to pay out the nose for music that *may* be what I'm looking for. Where is a decent repository of free sheet music?"
You are assuming that there have been no changes in musical notation since Bach and that there are no other significant problems in preparing a score suitable for modern performance.
If you are listening to a performance of Bach, it is almost certainly an orchestra's unique (and copyrighted?) interpretation of the work, and not an attempt at a mechanical, note-by-note, transcription of the score in manuscript.