it sounds like guitar with a wah wah pedal and flanger.. the wah pedal pretty much does what it sounds like it'd do - you press the pedal (like an accelerator pedal on your car) and as you step on it all the way (like revving your car) it makes a "wah wah" sound with whatever note you're playing..
The Flanger is another pedal which is more like an "on/off" trigger switch that gives your sound kind of a space warp kind of sound - hard to explain..
It sounds like the guitarist is "muting" his sound by not really pressing on the chords with his left hand, while his right hand is sweeping the strings - it just makes a muted sound and you speed it up, slow it down by how fast your right sweeps the strings with your pick..
Man, this is difficult to explain to someone who doesn't play or know the lingo.. if you want me to try and explain anything further, let me know.. there may be more going on that what I'm mentioning - I really am not SUPER familiar with the song - at least not to the point where I've listened and figured out what all is going on in it.. holler if you need to...
Friendship is like peeing your pants.. Everybody can see it, but only you can feel the warmth..