CD scratch is a free CD player for Windows that allows you to insert a CD into your drive and manipulate it in a variety of ways. You can use your mouse to make realistic scratching sounds, listen to a song backwards, change tempo and pitch and listen to two tracks at the same time. You can also set the player to automatically mix your CD or add crackling noises to simulate a vinyl record. Though this player is free, requires only 1MB of space and has no spyware or ads, it is limiting because you can only manipulate a single CD. Professional DJs usually mix beats from more than one album.
The Hip Hop DJ App is an application planned for the Apple tablet, intended for use with GarageBand. This application displays two virtual turntables that can play graphical representations of MP3 files being played. Users of this program can touch the virtual turntables with their fingers to stop and start a song, control the playback speed or "scratch" the virtual records.
The Virtual DJ program is used by established DJs in clubs and festivals around the world. The program is compatible with a variety of video file formats, timecode vinyl and CDs, and allows you to smoothly scratch music videos from a turntable or CD player. The program allows you to save cues and pitches, play seamless loops and access all of your music files at one time, so you can mix as many songs as you want.