obtaining license

[young'gun]

How would one go about obtaining a license for and footage of an old TV show a la Johnny Carson with the intent of editing and reproducing?
Is this possible or would costs be incredibly high?

[Frank]

There's a set of reference books called "Bowker's Complete Video Directory". It's a 4 volume set that has a listing for practically every video currently available, along with the distributor. Your local library may have a set in their reference section. It's a good place to start.