One of the very first songs I learnt as it is sooo easy!

Standard Tuning

Intro/Verse/Chorus

G:-----------------------------------
D:-----------------------------------
A:-----------------------------------
E:-7-7-7-7-7-7-7-7--0-0-0-0-0-0-0-0--

Change after every verse:

G:-----------------------------------
D:-----------------------------------
A:-----------------------------------
E:-5-5-5-5-5-5-5-5--4-4-4-4-4-4-4-4--

Bridge:

G:-----------------------------------
D:-----------------------------------
A:-----------------------------------
E:-2-2-2-2-2-2-2-2--0-0-0-0-0-0-0-0-- X2

After the second time

G:-----------------------------------
D:-----------------------------------
A:-----------------------------------
E:-3--------------------------------- hold it

Just before the last verse begins, there is a small bass line that adds to the song. Listen out for it!

G:-----------------------------------
D:-----------------------------------
A:-7-7-7-9-7-9-7--------------------- Keep your finger on the seventh.
E:-----------------------------------

Thats pretty much it, just continue with the verse then into the change and back into the verse. :p