Here is the intro to  track number 4 from All That You Cant Leave Behind
it is a track that i really like.  I have only learnt the chords that
Bono plays i am currently trying to practise The Edge bit but hey
he is a genius and i only been playing the guitar for 3 months so it may
well be a while before i perfect that. So goes

The 4 chords you need are

D
A
G
Em

you play them in that order and strum down 4 times on each chord.  You play
this twice and then to finish off you pull up on a D chord.  Try it sounds
like the real thing.