Mixxx - The most powerful free DJ software in the world.
VirtualDJ - Virtual DJ Software - MP3 and Video mix software for DJs
SoundGrail - SoundGrail Music App designed for pianists, guitarists, and DJs.
Aftertouch - Aftertouch – 3D MIDI Controller created and published by Kevin Nelson.
Mixmeister - Create custom party mixes, burn CDs, or add special effects to MP3s with this line of DJ software for the novice and pro. Offers free trials and user community.
keezy - A colorful soundboard. Play with music.