It is played on 7 string drop D

So i'm guessing it AEADGBE, cuz its a B droped down a full step... Not sure...

GTR I
E|--------------------------|
B|-5T12bT5T12bT3h5T12bT3----|
G|--------------------------|
D|--------------------------|
A|--------------------------|
E|--------------------------|
A|--------------------------|

This intro bit is a bit tricky, hold the 3 while you hammer the five and then tap/bend 
the 12 and flick back off to the 5 to get the desired effect... Its hard but sounds 
awsome if you do it properly.