This is a pretty big tree at this point and bigger trees have a much tougher time being moved.
I would not attempt this until the weather has cooled considerably and the tree is dormant (meaning it has dropped its leaves) -- it is too stressful for the tree now..
The root zone is going to be pretty big. You can start by root pruning it.
Here's an article that can help:
http://gardening.about.com/od/gardenprimer/g/RootPruning.htm
And here's a guide to determining the root zone:
A measurement of the trunk should be taken at diameter breast height (DBH) or 4.5 feet above the ground. Then measuring outwards from the trunk 1.25 feet for every inch of trunk diameter, the resulting area is the critical root zone. For example, a 20-inch diameter tree would require a 30-foot area of protection around the tree for the critical root zone. This is a minimum area of protection, but a larger area is preferred.