Program Name: MuseScore

Available languages: Over forty languages, including:
en af ar be bg ca cs da de et el es eo fa eu fo fr gl ko sr hr id it he lt hu nl ja nb pl pt ro ru sk sl fi sv vi tr uk

Compatibility with operating systems:
Windows 7 and 8 (32 - 64-bit), Vista, and XP
OS X 10.6+ Intel (64-bit, Core 2 Duo and up)
Linux: Ubuntu, Arch Linux, Debian, Fedora, Mageia, openSUSE, PCLinuxOS, Gentoo
Source Code Available

Type of License: GNU GPLv2

Author description: http://musescore.org/en/handbook/musesc ... escription
Create, play back, and print sheet music for free. MuseScore is cross-platform, multi-lingual, open source music notation software. It features an easy to use WYSIWYG editor with audio score playback for results that look and sound beautiful. It supports unlimited staves with up to four voices each, dynamics, articulations, lyrics, chords, lead sheet notation, import/export of MIDI and MusicXML, export to PDF and WAV, plus online score sharing.

Your opinion:
An excellent sheet music cration and playback program which is frequently used to generate backing tracks for solo artists. It can also convert MIDI into sheet music and vice-versa. MuseScore 2.0 Beta is quite stable and the extreme improvement from MuseScore 1.3 make it very much preferrable. I was able to easily setup MuseScore 2.0 to work well from LiberKey, so it should be an easy win.

A link to the author website: http://musescore.org/

A link to the download page: http://musescore.org/en/node/30866