Audacity Free audio and wave editor with some great effect plugins
AP Tuner - Free computer based guitar tuner
Anvil Studio- Free midi player and editor, play and edit midi files
Audio Odyssey Director- Submit your own music to itunes & more
Kangas Sound Editor- Create your own music and sound effects
AV Music Morpher Gold- Edit audio files split voice and music from a track
Expstudio Audio Editor - Record, edit, and manipulate audio files
WildVoice Studio 1.0.1.2502 - Record, create, and publish podcasts