Probably the most portable DJing software solution ever. Convert your audio both into mp3 and ogg, put it on a USB key with the ShanDJ.html file, and go DJ on any machine with a web browser newer than 2008.
Please both read this and refer to the project wiki for complete information.
If you are looking for a similar tool, but for use over internet instead of locally, you should take a look at Slcnc CMS, from the same developer, which integrates DJing over internet among other features.
- Music playback
Shandj works fine.