It's Matt again, I tabbed this by ear and I think it sounds about right. Be sure to add 
comments, corrections, requests, etc.

Intro
G-------------------------------------------------------|
D-------------------------------------------------------|
A-4-4-4-6---4-4-4-6---4-4-4-6---4-4-4-6-----------------|
E-------------------------------------------------------|

Chorus: "In you and I..."
G-------------------------------------------------------|
D-------------------------------------------------------|
A-0-0-2020--0-0-20202--4-4-7474--4-4-7474---------------|
E-------------------------------------------------------|

Verse: "I watch you..."
G------------------------------------------------------------------|
D-------2-2-2-2-2-------4-4-4-4-4-------4-4-4-4-4-------2-2-2-2-2--|
A-4-4-4-----------2-2-2-----------2-2-2-----------4-4-4------------|
E------------------------------------------------------------------|

Bridge, I don't know what she's singing, but in the Kingdom Hearts 2 Intro vid, This is 
Sora is running up the blue staircase and attacking heartless on the way up.
G-----------------------------------------------------------------|
D--------------------2-4-------------------24---------------------|
A--4-4-4-------4-4-4-----4-4-4-------4-4-4------------------------|
E--------45-45-----------------45-45------------------------------|

ORDER:
Intro x1
Chorus x4
Intro x1
Verse x2
Chorus x4
Bridge x2
Intro x1
Verse x2
Chorus x4
Short Pause
Chorus x4
Intro x1