I know thats probably not how to spell it but its not a sound with the amp. I think its way to do it with picking the strings.... I think its like after you play a not and before you play another... If you need more explanation then just ask but I just need an idiots guide to how to get that sound.
I think he means string muting. To dot that, after you do a chord, cover your left hand over the fretboard and with your right hand do a quick, or even slow, up and down stroke against the strings. I hope this is what you meant.

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it sounds like yu mean the sound tom morello gets on bulls on parade
you will need a wha wha pedal
now mute the strings while u pluck and move the wha wha pedal
one of my freidns has one i love to make that sound on
i think its like the string muting thing. but when I saw someone do it, it looked like they didn't move their hand, I thought they just kept it in the same position. I have a lesson today so I can ask but I was just wondering. I know it doesn't have to do with the wah wah pedal.