Typified by Morchella esculenta in 1794, the genus has been the source of considerable taxonomical controversy throughout the years, mostly with regard to the number of species involved, with some mycologists recognizing as few as three species and others over thirty. Current molecular phylogenetics suggest there might be over seventy species of Morchella worldwide, most of them exhibiting high continental endemism and provincialism. - wikipedia
A mess of fried morels is the Midwest equivalent of a halibut steak on the boat it was caught from. Their short seasonal availability and the difficulty of cultivating them makes them highly sought after and quite a special treat for those lucky enough to find them.
Luckily, morel mushrooms are quite prevalent in many parts of the world and a spring hike with a few honey holes can leave you enough bounty to feed the family and potentially even have a few left to sell. I have heard tales of them going for $40+/pound in large cities as they are a nice seasonal addition to many upper scale restaurants.
Morels will start to appear when the soil temps reach a consistent 45-55 degrees, and ambient temps hover in the 60's. For most Midwesterners that means, from late March-May, the week following a spring shower can trigger the growth of the fruiting bodies.
The best places to look are damp and well shaded. Often if you find one, you'll find more in the area due to the spores that have been spread from previous generations. Find a hot spot and you'll likely have luck there annually. Take the kids, and let them get in on the fun. There's few better ways to spend a nice spring day. Top it off with some fresh caught fish or pick a few while out on a spring turkey hunt and you'll feel like a King that evening at the dinner table!
The site below offers some great facts about morels, the care of them once harvested as well as several very intriguing recipes.
This site offers an annual morel summary report as well as a sighting page keen on when morels are starting to "pop" in your area.