Mixxx - The most powerful free DJ software in the world.
VirtualDJ - Virtual DJ Software - MP3 and Video mix software for DJs
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.
Traktor Pro - Flagship DJ software with four decks and a stunning range of creative features for maximum freedom in DJing.
Serato DJ - Serato DJ is award winning, digital DJing software used by professionals across the globe.
Pacemaker Editor - [You can still download last version of Pacemaker for Windows and Mac from Softonic: