So it starts off with the tinny intro riff thing and it goes like this.
e|--12--12--12-----12----12--12---|
B|--12--12--12-----12----12--12---|
G|--------------------------------|
D|14------14-----------14------14-|
A|----14------14-14--------14-----|
E|--------------------------------|

Then it goes into a riff that's like this: (oh and s means sweep, like slowly strum ya 
just listen to the original and try it and you'll see)
e|(S)12-14-12--------12-|
B|(S)12------14-12-14---|
G|(S)13-----------------|
D|(S)14-----------------|
A|----------------------|
E|----------------------|

Then its just variations of that moved down to A and once B to go with the chords. Just 
to the song and you should get it.