This song is in Drop D tuning - for me anyways...

Intro/chorus
the strumming, listen to the song
D I--7-/-5--/3--/5----------I
  I--7-/-5--/3--/5----------I
  I--7-/-5--/3--/5----------I
  I-------------------------I
  I-------------------------I
  I-------------------------I

verse
I--222-22-22-222-222----------I
I-----------------------------I
I-----------------------------I
I-----------------------------I
I-----------------------------I
I-----------------------------I

after the first chorus, its the same as the verse

after the second chorus 

I-2-0-0--3-3-3-0-0--5-55-/6--I
I----------------------------I
I----------------------------I
I----------------------------I
I----------------------------I
I----------------------------I

heavier
I-2-0-0--3-3-3-0-0--5-55-/6-66--I
I-2-0-0--3-3-3-0-0--5-55-/6-66--I
I-------------------------------I
I-------------------------------I
I-------------------------------I
I-------------------------------I

clean guitar after the third guitar
I-------------------------------------I
I--7-------7/5--7-----3------3/5------I
I----9------------------5--5----------I
I--------0----------------4-----------I
I------0----------0-------------------I
I-------------------------------------I