Denemo

I still have not tried this, but it could be useful:

Denemo is a music notation program for Linux and Windows that lets you rapidly enter notation for typesetting via the LilyPond music engraver. Music can be typed in at the PC-Keyboard, or played in via MIDI controller, or input acoustically into a microphone plugged into your computer’s soundcard.

Denemo itself does not engrave the music for printout – it uses LilyPond which generates beautiful sheet music to the highest publishing standards. Denemo just displays the staffs in a slim and efficient way, so you can enter and edit the music efficiently. [...]

Read more about its features…