Chris and I attended a Duck Hunting 101 course this past weekend sponsored by Ducks Unlimited. Ann has been a DU member since she started birding in earnest. Like TU, while most members are clearly sportsmen (and women), the conservation mission is forefront. They do for waterfowl habitat what Trout Unlimited does for coldwater species habitat.
Not only was the course itself worthwhile (especially because it was held in a conference room at Cabelas) but meeting fellow hunters who are as passionate about conservation as I am as an angler was refreshing.
If you have an opportunity, check out Ducks Unlimited. If you're a waterfowl hunter, I think this one is a no brainer to support.