The following list of software is not meant to be exhaustive, but it provides a wide range of  resources for creating and editing music....


RoseGarden: www.rosegardenmusic.com

Ardour: http://ardour.org

Hydrogen: www.hydrogen-music.org/

Jack: http://jackaudio.org/

LMMS: http://lmms.sourceforge.net/home.php

Audacity: http://audacity.sourceforge.net

Sweep: www.metadecks.org/software/sweep/

WaveSurfer: http://freshmeat.net/projects/wavesurfer/

Distributions with some of this software already installed:

Sabayon Linux: www.sabayonlinux.org/

DeMuDi: http://demudi.agnula.org/

Musix: www.musix.org.ar/en/