Here's the song as it is done live.

Intro and verse

e--------------------------------------------------------|
B--------------------------------------------------------|
G--------------------------------------------------------|
D--------------------------------------------------------|
A--------------------------------------------------------|
E--------------------------------------------------------|

The distorted screeches you can do either as harmonics of your choice, just have a lot 
feedback and compress it a lot, or you can play up behind the nut of the guitar.

Pre-Chorus

e--------------------------------------------------------|
B--------------------------------------------------------|
G--9--------12-----------8---------7---------------------|
D--x--x18----x-----x5----x---x18---x---x6----------------| x2
A--7--------10-----------6---------5---------------------|
E--------------------------------------------------------|

Chorus

A, G, Em (Listen and you'll figure the rhythm out, its easy)

Interlude

(This part is played by Wes only in a live situation)

e--------------------------------------------------------|
B--------------------------------------------------------|
G--------------------------------------------------------|
D---------------------5h7--------------------------------| x4
A---5-7-7--5-7-7-5-7--------5-7-7--5-7-7--5-7------------|
E----------------------------------------------6-5-------|

(At this point Steve kicks in and both guitars do this)

e--------------------------------------------------------|
B--------------------------------------------------------|
G--------------------------------------------------------|
D--------------------------------------------------------|
A--------------------------------------------5-4---------|
E--3p0-0---3p0-0--3p0--6-5-3p0-0--3p0-0-3p0--------------|

(Back to Wes only for another four bars, and then repeat the section with both guitars.)

Then, back to chorus.

Whilst one guitar does the chorus until the end, the other guitar kicks in with the outro.

Outro

e--------------------------------------------------------|
B--------------------------------------------------------|
G--------------------------------------------------------|
D--7--------5------2-------------7-5-7-5-----------------|
A--7-x16----5--x6--2--x6----5-6----------6-5-------------| x2
E--5--------3------0-------------------------------------|

And there you go, Halo live by PT. Enjoy.