Heat large nonstick skillet over medium-high heat. Add half of beef; cook, stirring to break up meat, for 5 minutes or until no longer pink. Drain in colander. Repeat with remaining beef.
Heat oil in pan. Add onion and green pepper; sauté 8 minutes or until softened. Add garlic and oregano; sauté 2 minutes.
Remove from heat. Stir in meat. Divide into fourths (about 4 cups each). Pack in plastic freezer bags or freezer storage containers; freeze for up to 3 months. Thaw in refrigerator.