Preheat the oven to 400 degrees. Lay the pancetta slices on a baking sheet lined with a sheet of parchment paper and cook (flipping once) for about 10 minutes or until browned and crispy.
Remove to a paper towel-lined plate and drain. Preheat a grill to medium/high heat and rub the peach halves with the olive oil and season with salt and pepper.
Mix together the brown sugar and vinegar and place a small spoonful on top of each peach halve as it grills. Cover and continue to grill an additional 4 minutes.