I'm not an EXCELLENT guitar player... really I'm pretty rubbish, but I can play 
quite basic chords so I figured out some basic ones to work for this song so that 
I could cover it and I figured I should share it because people have been asking a lot :)

I didn't use a CAPO but it'd obviously depend on your vocals as to how you'd use it idk

here's my cover that I used the chords so you can see how I played them?
http://www.youtube.com/watch?v=uStXpNF5G14

OKAY

--

                     C
Do you wanna build a snowman?

                    G
Come on lets go and play

                Am       
I never see you anymore, come out the door
 
                      G
It's like you've gone away

                   Am          C
We used to be best buddies and now we're not

  G                      D
I wish you would tell me why

C
  Do you wanna build a snowman?

Am
  It doesn't have to be a snowman

     C
Okay bye



C Am C Am 


                     C
Do you wanna build a snowman?

                             G
Or ride our bikes around the halls

                        Am
I think some company is overdue

                                            G
I've started talking to the pictures on the walls (Hang in there, Joan)

                 Am
It gets a little lonely

          C
All these empty rooms

     G                       D
Just watching the hours tick by

-no chords-
(Tic-Tock, Tic-Tock, Tic-Tock, Tic-Tock)



E, Am, Dm, D7


                      C
Please, I know you're in there

                               G
People are asking where you've been

                               Am
They say have courage, and I'm trying to

                                        G
I'm right out here for you, just let me in

                  Am
We only have each other
 
          C
It's just you and me

G                 D
What are we gonna do?

-no chords-
Do you wanna build a Snowman?

C G Am G C

--

Obviously it's no where near perfect but it's simple enough to sing to... 

HOPE THAT HELPS