Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan.
In a large bowl, cream together the sugar and butter until light and fluffy. Beat in the eggs one at a time, then stir in the sour cream and vanilla.
Combine the flour, baking powder, baking soda, and salt; stir into the batter just until blended. Fold in the peaches. Spread evenly into the prepared pan.
Bake for 45 minutes in the preheated oven, or until a toothpick inserted into the center comes out clean. Allow to cool before serving.