The first thing that I would do is call the NRD or the SCS. I'm not sure if they have the money anymore to help out with the cost, but I would think that they will still help you plan things. They'll help you with the proposed size based on watershed area etc.
Then go here
Pond Boss Magazine Home Page!. Click on the link that says "ask the boss" on the left side. This is the discussion board. You will realize how much you don't know, but the people there are always glad to help.