Ohio State University
Ohio State University: Wild Mushrooms
This site from the Ohio State University talks about poisonous and edible mushrooms, and shows some species of each.
Other
Mdc: Edible and Poisonous Mushrooms
This site gives three different illustrations of edible wild mushrooms. Along with each illustration is a brief description of the mushroom, including where and when it can be found, cautions you should be aware of, and cooking tips for...