Preheat oven to 425°.
Combine potatoes and oil in a large bowl, tossing well to coat. Combine salt, garlic powder, and pepper in a small bowl. Sprinkle salt mixture over potatoes, tossing well to coat. Arrange potatoes in a single layer on 2 baking sheets coated with cooking spray. Bake at 425° for 25 minutes. Turn potato wedges over, and rotate pans; bake an additional 20 minutes or until golden brown.