1. Remove giblets and necks from ducklings. Rinse ducklings, giblets, and necks with running cold water; drain well. Pat ducklings dry with paper towels. Cut each duckling into quarters; trim excess skin and fat from pieces.
2. Place duckling quarters, skin side up, on rack in large open roasting pan; sprinkle lightly with salt and pepper. Roast in 350°F. oven about 2 hours or until ducklings are golden and fork-tender.
3. Meanwhile, in 3-quart saucepan over high heat, heat giblets, necks, 1/4 teaspoon salt, and enough water to cover to boiling. Reduce heat to low; cover and simmer 1 hour or until giblets are tender. Drain, reserving 1 cup broth. (Refrigerate giblets, necks, and remaining broth to use in soup another day.)
4. In 2-quart saucepan, combine port wine, orange juice, lemon juice, mustard, ginger, 1/2 teaspoon salt, 1/2 cup currant jelly, and reserved 1 cup broth; over medium heat, heat to boiling. Reduce heat to low; cover and simmer 10 minutes to blend flavors. In cup, mix flour and 1/4 cup water; gradually stir into simmering liquid in saucepan. Cook over medium heat until sauce thickens slightly and is smooth.
5. About 10 minutes before ducklings are done, in cup, stir 1/4 cup currant jelly and 1 tea spoon water until smooth; brush duckling quarters with jelly mixture.