"We've Just Begun to Dream" was used extensively during the opening ceremonies at Epcot. I know for a fact that it was used during the park's main grand opening ceremony, as well as the Communicore grand opening ceremony. This video footage is available to cast members via the WDW Centers of Excellence. It's almost worth getting a job there to see the videos! The choreography is very... 1982.

Here are the lyrics as I transcribed them:
In you heart there’s a place,
a magical space, where it all begins
With your life as a guide,
You light up inside, and it starts to spin
Just close you eyes, and dream of things to come
In dreams, we make tomorrow
We’ve just begun
We’ve just begun, we’ve just begun
Open your eyes
A fantasy in time
Open your eyes to find, a brand new world
A shining star………
A new creation
It’s all around you
A celebration
A celebration
A new sensation
It will astound you
A celebration
A celebration
An inspiration
A fascination
A celebration
A celebration
A celebration
A better nation
Imagination
Celebrate, as we create
A new tomorrow
Celebrate, a dream is made?
A new tomorrow
The world awaits, celebrates
A new creation
Celebrate, celebrate
Imagination
We’ve just begun, we’ve just begun
To dream…….
Other than that, I'm not sure where else it was used, aside from the previously mentioned references.
- innoventionseast