i was just looking for an easy way to play this song, and this is what i came up with.

when you play "o're the land of the free", you jump to a G if you're harmonizing 
with a Bb. otherwise, stay on a D

CAPO ON THE FIRST!!!!

D  G
Oh say can you see, 
                  D 
by the dawn's early light,
        G            D              G  
what so proudly we'd hailed, at the twilight's last gleaming?
D           G                  
Who's broad stripes and bright stars, 
                D
through the perilous fight,
         G             D               G
O're the ramparts we'd watched were so galantly streaming?
                    D                            C
And the rockets red glare, the bombs bursting in air,
     G                 D
gave proof through the night, 
         G
that our flag was still there.
D G             C             D           
O say does that star spangled banner yet wave
         G           D   G
o're the land of the free___,
        C       D   G
and the home of the brave?