I got an itch, (in Off-topic)

and it needs to be scratched... As in dubstep scratched.

I want to make my own dubstep, and I need some music programs that will strip out parts of songs and let me mix and match.

Know any I should invest in?

Lol, thought it said inch.

Here is one amazing audio tool, I managed to create a crappy song with it, and it is similar to FruityLoops, but this one is free:
http://burn-studios.audiotool.com/

An audio mixing tool, not quite as feature packed as Audiotool, but has a lot of samples built in.
http://www.looplabs.com/

Audacity is now a multi-track audio editor, and it can load MP3s to mix songs on different tracks. I've used it before and it's great:
http://audacity.sourceforge.net/