TonsOfTabs [http://www.tonsoftabs.com]
tune guitar to:
(E,a,d,g,b,e)

intro and main riff (gtr.1)
}--0-0--0-0-0--0--0-0--0-0-0-0-sl./-------------------------------------------{
}--0-0--0-0-0--0--0-0--0-0-0-0-sl./-------------------------------------------{
}--8-8--8-8-8--8--8-8--8h9-9-9-sl./-14-14--14-14-14-14--14--14-14-13-13-11----{
}--9-9--9-9-9--9--9-9--9-9-9-9-sl./-14-14--14-14-14-14--14--14-14-14-14(14)---{
}--7-7--7-7-7--7--7-7--7-7-7-7-sl./-12-12--12-12-12-12--12--12-12-12-12(12)---{
}--*-*--*-*-*--*--*-*--*-*-*-*------------------------------------------------{
     E                                                     A

on top of this, another guitar is playing just straight E and A chourds
in almost the same pattern

intro and main riff (gtr.2)
{-0-0--0-0-0--0--0-0--0-0-0-0---0-0--0-0-0-0--0--0-0-0---/-(0)-0--}
{-0-0--0-0-0--0--0-0--0-0-0-0---0-0--0-0-0-0--0--0-0-0---/-(0)-0--}
{-1-1--1-1-1--1--1-1--1-1-1-1---6-6--6-6-6-6--6--6-6-6-sl./-(8)-8-}
{-2-2--2-2-2--2--2-2--2-2-2-2---7-7--7-7-7-7--7--7-7-7-sl./-(9)-9-}
{-2-2--2-2-2--2--2-2--2-2-2-2---7-7--7-7-7-7--7--7-7-7-sl./-(9)-9-}
{-0-0--0-0-0--0--0-0--0-0-0-0---5-5--5-5-5-5--5--5-5-5-sl./-(7)-7-}


Chorus

}-----------------------------------------------------------------{
}-----------------------------------------------------------------{
}-----------------------------------------------------------------{
}-7----6--6-4--4-4-4-4-4-4-4-4-4-6-6-7--7-7-7-7-7-7-7-7-7-7-7-----{ 
}-7----6--6-4--4-4-4-4-4-4-4-4-4-6-6-7--7-7-7-7-7-7-7-7-7-7-7-----{
}-5----4--o-2--2-2-2-2-2-2-2-2-2-4-o-5--5-5-5-5-5-5-5-5-5-5-5-----{ (repeat)
                                                    ^the chourus will end about
                                                 here and go back to the main riff 
                
a white horse.....(2nd verse is the same just go to the top again)