Preheat oven to 400°.
Place pitas on a large baking sheet. Bake at 400° for 8 minutes, turning once. Cool slightly on a wire rack.
Spread about 1/4 cup beans over each pita. Top each pita with 2 tablespoons salsa and 2 tablespoons cheese. Place pizzas on a large baking sheet. Bake at 400° for 8 minutes or until cheese melts. Remove from oven. Top each serving with 1/4 cup lettuce and 1 tablespoon sour cream.