I had never experienced crawdads until I came to Oregon, although they can be found in rivers throughout the country. They are very popular in the Southern States and they can make an excellent meal if you are willing to do a bit of work.
First you'll need to find the crawdads. There are quite easy to find and there are many methods of catching them. Commercial traps are available, but I've found that getting into the river and "flipping rocks" over where they hide will yield the most crawdads in the shortest period of time. They do have claws which can give you a good pinch, so some people will wear rubber gloves to protect their hands. Once you flip the rocks just grab them with your hands or a net and drop them into a bucket. Make sure to refresh the water continually because you will want to keep them alive for the trip home.
To cook and clean your crawdads is really quite easy. They cook much like crabs. You need to place them in salted boiling water for about 18 minutes. Their color will change from a dull orange the a bright orange as seen in the pictures below. The majority of the meat is in the tail and all you need to do is bend the tail outward to expose the meat. Many people like to break off the heads and then just suck out the insides, and the taste is sweet and very close to that of Lobsters.
I would suggest that for a good meal that you have about 30 for each person, and seasoning in dependent upon your taste. A bit of lemon is excellent, and some people like a bit of hot sauce on them. They can also be served over rice or other vegetables or made into a delicious crawdad soup.