WaveShop - Open source audio editor
Bosca Ceoil - A free, easy to use tool for creating music.
TwistedWave - TwistedWave is one of the unique audio editors that allow you to edit your music file online without any installation.
Zynewave Podium - Podium is a modern digital audio workstation (DAW) for Windows.
Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
Renoise - Renoise is a digital audio workstation.