They aren't edible, but some people report that they can be used to keep moles out of your yard.
Bignonia Catalpa
Catalpa - The Indian Bean Tree
It could be a Catalpa (http://en.wikipedia.org/wiki/Catalpa).
Japanese Empress Tree or Paulownia tomentosa
The scientific name for the Northern Catalpa is Catalpa speciosa.
The Catalpa beans are not edible, but have several uses. Indians used many parts of the tree for medicines and some say they can be used to keep moles out of a yard.
Catalpas are not Legumes, as I thought for many years. They are low-level N fixers, but belong in the family Bignoniaceae.
Catalpa speciosa
the Northern Catalpa
Catalpa ovata was created in 1837.
Catalpa is a family of beautiful late-summer flowering trees mostly low and spreading in habit. Older trees bear panicles of foxglove like flowers . Do not plant in exposed areas as the large leaves will shred with the wind. The variety bignonioides, the Indian Bean tree is one of the best.
I haven't tried to grow a catalpa from seed. However, the way that catalpa seedlings grow abundantly near mature trees I have observed--both in eastern and western Massachusetts--suggest they grow easily. My theory is that snow plowing has a lot to do with getting the beans buried and off to the sides of roads or parking lots, where they manage to grow without interference from lawn mowers or other controlled landscaping.