ACID XPress
It is easy to create original music even if you are new to loop-based music software. This is a tool for creating original loop-based music, where a composer uses variations on repeating music samples to create songs. Download the software and use the built-in sound samples or your own recordings to make music.
Development: Sony Pictures Digital Inc.
Type: Music Sound
License: Free Noncommercial

Frets on Fire
The gameplay that is a music video game similar to Guitar Hero - the player emulates playing a guitar. FoF is meant to be played by picking up the keyboard like a guitar, with one hand pressing the fret buttons and another pressing the pick button. Players use the keyboard to play along with on-screen musical notes.
Development: Unreal Voodoo
Type: Music Game
License: Free Noncommercial

Free Audio DJ Mixer
A multi-file audio player. It features a simple and useful play list, a lengthy time recorder, and an audio-level monitor and tester. It supports MP3 and WAV so it can act as a converter from MP3 to WAV. Choose from included music or select your own MP3s and then step up to the turntables and start mixing.
Development: SoftwareClub
Type: DJ software
License: Free Noncommercial

Finale NotePad
Finale NotePad is your invitation to the world of music notation software! Find out how fun and easy it is to transform your musical ideas into beautifully printed music by downloading NotePad today! NotePad for Windows, Windows XP/Vista Internet connection or CD-ROM drive (for installation) required
Development: MakeMusic Inc.
Type: Music
License: Free Noncommercial

Audacity
Audacity is free, open source software for recording and editing sounds. It is available for Mac OS X, Microsoft Windows, GNU/Linux, and other operating systems. Audacity won the SourceForge Community Choice Awards 2007 -- Multimedia Category, audio editors, recorders, sound editing, free music creator.
Development: GNU General Public License
Type: Sound
License: Free Noncommercial

HammerHead Rhythm Station
Aimed at the dance scene, HammerHead is a simple software drum machine similar to the Roland TR-909. You can use it to create techno loops and jungle patterns, and record your actions to a high-quality, noise-free WAV or RAW file for use with your sampler or sequencer, music making software creator.
Development: Bram Bos - VST
Type: Music Sound
License: Free Noncommercial

FL Studio fruityloops
FL Studio is the best most complete virtual studio currently available. It will play any sample file (wav), generator (softsynth), VSTi & DXi) or midi instrument you feed it. You will be creating wav, mp3 or midi songs or loops only minutes after launching it. The best way to experience it is to download the demo.
Development: Image Line Software
Type: Music Sound
License: Commercial

Xilisoft iPod Rip
As all-around iPod rip software, Xilisoft iPod Rip supports transferring music, videos and photos among iPod, iPhone and PC, and importing files from iPhone to iTunes. It helps you easily create, edit and delete iPod playlists and manage multiple iPods at the same time. Limited to 10 files in batch mode.
Development: Xilisoft Corporation
Type: Music Sound
License: Commercial