I think I mentioned this one other time, but a colleague of mine has made a 3 dvd set of wild plants of the midwest. From his website :

10 yrs in production!

A 3 volume DVD set. Nearly 100 plants. Gives visual identification,
edible, medicinal, and utilitarian uses of plants and trees

Each volume has an easy to use "Usage Index"

Gives Latin, common, and general Native American
name translations, Approximately 3 1/2 hours in length

The only DVD set of its kind in the midwest region

Many of the plants extend from Texas to Canada

Useful for professional ethnobotanists, botanists, herbalists, as well as avocationals interested in plant identification and usage

The DVDs have excellent images (he's an award-winning professional photographer) and cover a wide variety of plants. Main drawbacks are dvd format - hard to take in the field - and it's a little spendy ($39.95 + $5.00 US shipping). I asked him about the possibility of a book, he just rolled his eyes and said never again. This was a labor of love and not a money-making endeavor. Which leads to the disclaimer: No financial connection, although I consider Rick and Doris friends.