@purplespark: You can cook a duck on a roasting rack but I really think that cooking one in the oven is the best way to go. I can give you some pretty simple instructions.
Preheat your oven to 375 degrees. Place the duck on a chopping board and remove the excess fat, usually around the body cavities and neck. Rinse the duck very well, inside and out, under cold water. Pat dry with a paper towel.
Pierce the skin of the duck all over. I use my ice pick to do it. Rub salt and pepper into the skin, inside and out. Place the duck on a rack placed in a roasting tray, breast side up. Pour a few cups of boiling water over the duck and into the roasting tray and place in the oven. Roast for up to 3 hours or until no fat remains and the skin is crispy and brown. Turn the duck over after every 30 minutes. You can also baste the duck with the juices enhances the flavor.
Once the duck is cooked, remove from the oven and transfer it to a carving board.