An article today in the New York Times about food from the wild refers to collecting berries and sour cherries, also known as Morellos.
A couple of books are recommended so that you can identify fruits in the field and collect only those items that won't poison your family. They are "A Field Guide to Edible Wild Plants: Eastern and Central America" by Lee Allen Peterson and Roger Tory Peterson (Houghton Mifflin, 1999) and "Identifying and Harvesting Edible and Medicinal Plants in Wild (and Not So Wild) Places" by Steve Brill (William Morrow/ Harper Collins, 1994).