First tab :)
The whole song is basically D A Bm G
But here's an example of when to change.
For the rest of the verses just listen to the song and you'll pick it up pretty easy :)

D (xx0232@1)                                 AI'll (x02220@1)put a message in a bottle and I'll throw it across the sea
Bm (x24432@1)            GYour (320003@1)the lock and included is the key
D (xx0232@1)                 AAlong (x02220@1)with a dozen x's and o's
Bm (x24432@1)            GLord (320003@1)knows that you can't get enough of those
D (xx0232@1)                       AYour (x02220@1)superkalafragelisticexpialadociously cute
Bm (x24432@1)         GSweeter (320003@1)than a 12 pack of juicy fruit
D (xx0232@1)              ASurreal, (x02220@1)but I know this isn't a dream
Bm (x24432@1)             GWe (320003@1)go good together just like coffee and cream