MuseScore is a music scorewriter for Linux, Microsoft Windows and Mac. MuseScore is a WYSIWYG editor, complete with support for score playback and import/export of MusicXML and standard MIDI files. Percussion notation is supported, as is direct printing from the program. The program has a clean user interface, with fast note editing input similar to the step-time note entry found in the popular commercial Scorewriting software packages, Finale and Sibelius.
For additional information, please refer to: MuseScore: LSU Overview.