| He is using harmaonics. I think he might tap a little bit but the main melody is harmonics. It is very easy to learn once you know which frets give you harmonics. I'm sure there are multiple resources about this on the internet so just search for harmonics. For starters, it is when you put your finger over the fret (the actual bar) and don't press down. Pluck the string and quickly remove your finger. The note will resonate after you remove your finger. That is just scratching the surface. There are false harmonics, cool chords, and a whole bunch of other stuff. On the Live at Bass Day DVD I think during the additional interview he talks about harmonics. It's not on the VHS, though. Listen to "Portrait of Tracy" by Jaco for a great example of harmonics. | 
