The chorus chords are: G / Am / C / Em

Far as I can tell, the only chords in the song are G / Am / C / Em

It starts on Em, strum along until you change to G (listen to the recording to get it 
it's on the '...four walls' line. The sequence of chords for the verses go:

Em / G / Em / Am

then

C/ (x32010@1)G/ (320003@1)C/ (x32010@1)Em (022000@1)then off to the chorus so it goes... (lyrics waaaaay off!)

G (320003@1)                Ama (x02210@1)beep beep beep
C (x32010@1)                   Emit's (022000@1)a home for me
G (320003@1)                    Amscream (x02210@1)scream scream
C (x32010@1)                                  Emoh (022000@1)the happiest place to be.

Sorry there's no real detail but it's such an easy song (although a great one), if you 
play open chords and know the recorded version (on the bside of 'Well, love does furnish 
life') then you're laughing. Enjoy.