Preheat oven to 400°F. Mix brown sugar, 2 teaspoons of the cinnamon, ginger and salt in small bowl. Toss sweet potatoes with oil in large bowl. Add spice mixture; toss to coat well. Spread sweet potatoes in single layer on shallow baking pan sprayed with no stick cooking spray.
Bake 30 to 35 minutes or until sweet potatoes are tender and lightly browned, turning halfway through baking time.
Meanwhile, mix sour cream, yogurt, honey and remaining 1/2 teaspoon cinnamon in small bowl. Serve sweet potatoes with dip.