In a large bowl, mix the vinegar, oil, garlic, basil, salt, and ground pepper. Place the shrimp, bell pepper, and onion in the bowl, and gently toss to coat. Cover, and allow to marinate at least 20 minutes in the refrigerator.
Heat a pan grill over high heat. Alternately thread the shrimp, onion chunks, and pepper chunks on skewers.
Place skewers on the pan grill, and cook 2 to 3 minutes per side, until shrimp is opaque.