Soak prunes and apricots in Madeira for 30 minutes. Strain, saving liquid. Mix together prunes, apricots, 1/4 teaspoon salt, and rosemary. Reserve.
Slice off extra fat from pork. To butterfly pork, cut loin lengthwise, slicing to, but not through, other side. Open the halves, laying pork flat. Cut each half lengthwise, slicing to, but not through, other side; open flat. Arrange heavy-duty plastic wrap over pork, and pound to an even thickness, using a meat mallet or rolling pin. Spoon prune mixture down middle of pork to within 1/2 inch of sides.
Wrap up pork like a jelly roll and tie at 2 inch intervals with string. Season surface with salt and pepper.
Preheat oven to 350 degrees F.
Lay pork, seam side down on a cooking spray coated baking sheet. Bake 1 1/2 hours or until a meat thermometer reads at least 160 degrees F. Brush pork with extra Madeira while baking.
Move pork to a serving platter and let stand 10 minutes before slicing.