The film does not have an official title, but most people call it the EPCOT movie. You can view it on the Walt Disney's Tomorrowland DVD, from the Walt Disney Treasures line.
Disney has used it many times to promote the current EPCOT, which is somewhat of a travesty. In case you didn't know, EPCOT of today is nothing like what Walt envisioned. Mine is not the place to go into that, but Walt Disney was dreaming of something revolutionary, not just another theme park.
The film describes Walt's vision for the community of EPCOT, featuring a central city business district, with concentric circles following out to the edge of the city. In between are various entertainment options, including an amusement park, movie theatre, park and more. People movers, monorails and other forms of transportation keep cars off the roads, keeping the air clean and traffic to a minimum.
If this had been ultimately completed, it could have been Walt's ultimate gift to the world - a new way to plan communities and cities. After his death, EPCOT would never be completed the way that Walt planned. The remaining executives lacked the guiding force to make the vision a reality, and EPCOT became EPCOT Center, the theme park.
But for a few moments, Walt's vision was a reality, in this film. A model of it was built, and can be seen now in the Tomorrowland Transit Authority, and you can see the sets of the film at the One Man's Dream attraction in the Disney-MGM Studios. I advise everyone to see the film if you can, it's a true insight into Walt and his world.