this riff is very easy, and you need the whammy pedal to use it (not whammy bar, the 
pedal)

e|--------------------13 >--13 --10 ------------------------------------------------------|
D|-----------------------------------------------------------------------|
A|-----------------------------------------------------------------------|
E|-----------------------------------------------------------------------|

pedal up= >
pedal down= <

btw, set your pedal to up one octave...not down one, or up two or something wierd like that