David,
Well, how large is large? Are we talking a 30' tall tree, a 12' tree, or a 60' tree? Is the tree 2 inches is diameter or 20 inches in diameter?
If you are dead-set on moving this tree, I would strongly suggest you contact a certified arborist or tree care specialist as located in the yellow pages. Much care is required and much preparatory work is needed to ensure a successful transplant.
If you can provide me with more details and specifics, then I might be able to provide you with a better action plan :-) Otherwise, you will need to contact a tree care specialist and request on-site assistance.
Best of luck!