Trim fat from pork; cut pork in 1-inch cubes. Peel, core, and chop two apples; set aside. In a 4-quart Dutch oven brown pork, half at a time, in hot oil; return all pork to pan. Add chopped apples, onion, and curry powder; cook and stir 2 minutes. Add broth, cider, salt, and pepper. Bring to boiling; reduce heat. Simmer, covered, 30 minutes, stirring occasionally.
Add carrots and celery to pork mixture; return to boiling. Reduce heat; simmer, covered, 20 minutes, stirring occasionally. Cut remaining apples into 1/4-inch-thick wedges. Add apples and squash to pan. Cover; cook 10 to 12 minutes or until pork and vegetables are tender. Serve with sour cream, orange peel, oregano and pepper. Makes 6 servings.