Very easy. Listen to the song for the strumming pattern, but it's basically two
down strokes on the C and then down/up/down on the other chords. 

C Em F                 G       C Em
Play something that we need to hear
F                G        C Em
Play to make the ghosts appear
F          G           C Em F G
Play until the bottles gone

That chord sequence is then repeated through the song, until:

Em             Am
Play it in the streets, Play it in the schools
F               F                      G              G           C Em F G 
Play it for the ones out there who?ve never seen what playing can do

Then it returns to the main chord sequence until the end of the song.

Pretty simple, but a great song.