mapping unwanted fruit trees

One of the mailing lists I'm on has seen a flurry of mentions for free fruit from trees that no one wants or have too much of. In addition,while walking the dogs in the around the neighborhood I've noticed a lot of fruit trees with rotting fruit on the ground. I'm wondering how difficult it would be to map the locations of the various trees and talk with the owners about harvesting the unwanted fruit and either giving it directly to a food bank or preserving it via caning, freezing, ... then give it to the food bank.