Thats pretty cool man. I got a spider.
Also, the sound is generally whats known as a pinch harmonic. It has to deal with skill, rather then your amp or guitar, however it becomes easier depending on the equipment or settings you use. It's basically done by playing a note, and just as you pick it, let the pad of your thumb graze the string every so slightly to offset the sound to reach the harmonic range
Search pinch harmonics on youtube, I would think you could find something on there about how to do it proper. It's actually really easy once you get a feel for it.