Some people play this one step up, I listened to the song and I think you can play it 
way but this one sounds better.

Intro (also played during the first verse):
E----0-----0-------------------|
B---1-1---1-1---1-3-1---1-3-1--|
G--2-----0---------------------|
D--------------3-------3-------|
A------------------------------|
E------------------------------|

Am        C               F
I can't believe the news today
Am       C                F
I can't close my eyes and make it go away

 C         Dm
How long?  How long must we sing this song?
 C          Dm
How long? How long?...
       C        Dm                  C        Dm
'Cause tonight, we can be as one, tonight.

Am      C            F
Broken bottles under children's feet
Am     C                 F
Bodies strewn across the dead-end street
Am          C               F
But I won't heed the battle call
Am         C                F
It puts my back up, puts my back up against the wall

Am  C          F
Sunday, Bloody Sunday
Am  C          F
Sunday, Bloody Sunday
Am  C          F
Sunday, Bloody Sunday
Am  C          F
Sunday, Bloody Sunday
Oh, let's go

Am      C              F
And the battle's just begun
Am           C                 F
There's many lost, but tell me who has won?
Am           C              F
The trenches dug within our hearts
Am            C                  F
And mothers, children, brothers, sisters torn apart

Am  C          F
Sunday, Bloody Sunday
Am  C          F
Sunday, Bloody Sunday

 C         Dm
How long?  How long must we sing this song?
 C          Dm
How long? How long?...
       C        Dm                  C        Dm
'Cause tonight, we can be as one, tonight.

Am  C          F
Sunday, Bloody Sunday
Am  C          F
Sunday, Bloody Sunday

                Am        C    F
Wipe your tears from your eyes
           Am    C   F
Wipe your tears away
                Am    C   F
I'll wipe your tears away
                Am    C   F
I'll wipe your tears away
                Am        C   F
I'll wipe your bloodshot eyes
Am  C          F
Sunday, Bloody Sunday
Am  C          F
Sunday, Bloody Sunday

Am               C     F
And it's true we are immune
Am               C     F
When fact is fiction and TV reality
Am               C     F
And today the millions cry
Am               C     F
We eat and drink while tomorrow they die
Am               C     F
The real battle's just begun
Am               C     F
To claim the victory Jesus won
On...

Am  C          F
Sunday, Bloody Sunday
Am  C          F
Sunday, Bloody Sunday

Hold Am to finish.

Hope you enjoy, great song BTW. It's not hard to learn the chord pattern, and the intro 
out easily with practice.