Heat 2 tablespoons of oil in a skillet over medium heat. Add the beef and brown on all sides. Transfer to crockpot. Add remaining 2 tablespoons oil to the skillet and saute the onions and green peppers until soft. Transfer to crockpot. In crockpot stir in the jalapenos, chili powder, oregano, cumin, salt and beer. Cover and cook on LOW 6 to 8 hours or on HIGH 3 to 4 hours.