1. Wash the pigs' feet well. Place them in a large pot and pour in the water. Add the vinegar, onions, green peppers, red pepper, salt, and black pepper. Heat to boiling over medium heat. Reduce the heat to simmering and cook, covered, until just about tender, about 2 1/2 hours. Skim the surface and stir the pigs' feet occasionally during cooking.
2. Preheat the oven to 350 degree F. Remove the pigs' feet from the broth with a slotted spoon. (Reserve the broth for cooking greens or vegetables.) Arrange them side by side in 2 baking pans large enoughto hold them in a single layer. Spoon the barbecue sauce over them and bake 15 minutes. Reduce the heat to 300 degree F. and continue cooking until tender, about 35 minutes.