I love the version of this song and it's pretty simple to play.
Just stick a capo on the 3rd fret and play Em G D C throughout the whole song...
Today is gonna be the day
That they're gonna throw it back to you
By now you should've somehow
Realized what you gotta do
I don't believe that anybody
Feels the way I do about you now
Etc. Etc. :)
-Kieran