There are basically two chords for the intro, G4 and D4. I play them as follows:

G4:         D4:
 E|3            E|10
 B|3            B|10
 G|5            G|12
 D|5            D|12
 A|5 (or 3)     A|12 (or 10)
 E|3            E|10

The parentheses are an alternative way of playing it that also sounds good.

Following that, it goes (for the most part) G, D, C.

And then there's this part, which I'm not even sure if a guitar is playing but its the 
transcribed to guitar:

E|--3-5-7--7--3-5-3--0--3--7-7--3-5-3--0--3--5--5--7-5-3--0--3--3--3-2-0-----|
B|------------------------------------------------------------------------3--|
G|---------------------------------------------------------------------------|
D|---------------------------------------------------------------------------|
A|---------------------------------------------------------------------------|
E|---------------------------------------------------------------------------|

E|--3--5--5--7-5-3--0--3--3--|
B|---------------------------|
G|---------------------------|
D|---------------------------|
A|---------------------------|
E|---------------------------|