Preheat oven to 400 degrees. Place paper liners in 18 muffin cups and set aside.
In bowl of mixer combine flour, sugar, baking powder, baking soda and salt. Add butter and cut in with two knives or a pastry cutter until it looks like coarse crumbs.
In separate bowl mix yogurt, orange juice concentrate and eggs. Pour into flour mixture and mix just until combined. Fold in fruit.
Fill muffin cups and bake 15 min., or until toothpick comes out clean. Let muffins cool for 10 min. and then remove from muffin tray to cool completely.
(adapted from Weight Watchers "Simply the Best- Cranberry-Blueberry Muffins")