look for a program called TRAKTOR DJ Studio 2.0:
I use it and it rocks. ts like having two turntables on your PC.
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Professional DJ Software
Now available for PC, Mac OS 9.2, and Mac OS X.
TRAKTOR DJ Studio 2.0 is the most powerful and versatile software solution for professional DJ mixing, live remixing and mix recording using tracks in MP3, WAV, AIFF, and Audio CD* format.
Unique tools for advanced DJ mixing
TRAKTOR DJ Studio 2.0 exceeds the possibilities of traditional DJ equipment by implementing a vast range of mixing features that only software can provide.
This includes graphic waveform displays, tempo recognition and automatic synchronization, up to 10 cue points and 10 tempo-precise loops per track, and a track database with ultra fast search function.
TRAKTOR DJ Studio 2.0 was developed in cooperation with professional DJs and opens up a whole new world of real-time mixing and remixing possibilities.