well, the sound has to come from somewhere....and that somewhere sound is then captured and made to sound cool just like you would with any other type of music, so in the big picture....think REMIX and think DRUM MACHINE.
So here are just some tools you might find useful.
First of all MixMeisterPro (or Audacity for a bit more simplicity). These are perfect for making mixes and stuff. Easy to learn, fun to use.http://www.mixmeister.com/
some live djing software:
Traktor DJ Studio : http://www.native-instruments.com/in...tor_us&flash=7
and PCDJ : http://www.visiosonic.com/
All Around Good tool: Fruity Loopshttp://www.fruityloops.com/
for linux: Hydrogen: http://www.hydrogen-music.org/
i believe FL has a drum machine for windows.