I like the worms music it's pretty cool but it would still be way cooler if i could here my own custom music when i play worms. I was wondering if there's a way to change the music that plays when your playing th game,... does it have anything to do w/ whats in the streams folder or am i completely off thanks in advance?!!!

Yes, ..\Data\Streams contains all the music.
You would have to burn an edited CD or mount an edited disk image as virtual drive with those .wav files substituted by your own.
Quite inflexible though.

I suggest to simple disable ambience music in the options (cross it out) and use an external audio player like Winamp to listen to your own music.
If your keyboard has extra multimedia buttons, you can easily control Winamp with them from within the game.
If not, Winamp has it's own Global Hotkey feature to configure custom shortcuts.