In a large bowl stir together garlic, minced rosemary, and 3 tablespoons oil and add shrimp. Marinate shrimp, covered and chilled, at least 4 hours or overnight. In a shallow dish soak skewers in water to cover 30 minutes and prepare grill. To grill, thread 4 shrimp on each skewer and brush with additional oil. Grill shrimp on an oiled rack, set about 5 inches over glowing coals, 3 to 4 minutes on each side, or until just cooked through. Alternatively, brush shrimp with additional oil and grill in a hot well-season ridged grill pan, covered, over moderately high heat 3 to 4 minutes on each side, or until cooked through. Garnish shrimp with rosemary sprigs and serve with lemon wedges. Serves 4. Gourmet June 1994