CDW,
Dave is right, clay is needed to hold water. If you can find it on your property, that is the easiest way to go. And, by the way, the cheepest. If you have no clay to work with, you are going to have to bring it in. If not, a liner or a chemical barrier would have to be used.
Sounds like you are on the right track. Learn all you can before moving dirt or signing anything.
One other thought, have you talked to a local pond builder? They are usually some of the best sources of information. Ask the neighbors about a reputable pond builder and start there.
Best of luck, post pictures and questions when you can.
