The basic riff is as follows :)

e|---------------------------------------------------------------------------|
B|----------------------------------------------8----8----10----10----12-----|
G|-------9-----9-----11-----9------11----------------------------------------|
D|---------------------------------------------------------------------------|
A|----9-----9------9-----9------9--------------------------------------------|
E|-------------------------------------------8-----8----10---10-----10-------|



e|---------------------------------------------------------------------------|
B|-------5-----5----6----5----6------------8----8----10----10----12----------|
G|---------------------------------------------------------------------------|
D|---------------------------------------------------------------------------|
A|---------------------------------------------------------------------------|
E|----5-----5----5----5-----5-----------8----8-----10----10-----10-----------|

Theres a few variations I think but that works pretty much most of the way through :)