One recipe for pork carnitas comes from FoodNetwork.com. It calls for pork shoulder to be cooked in a slow cooker with spices, garlic, peppers and citrus juice.
To make pork carnitas, rinse and dry 2 pounds of boneless pork shoulder and season with salt and pepper on all sides. In a small bowl, mix 2 teaspoons of dried oregano, 1 teaspoon of cumin and 1 tablespoon of olive oil. Rub this mixture all over the pork shoulder. Place the pork into a slow cooker and top it with 1 coarsely chopped onion, 4 minced cloves of garlic and one chopped jalapeño pepper. Cut an orange in half and squeeze the juices over the top of the pork, then add the halves.
Put the lid on the slow cooker and cook on low for 8 to 10 hours or on high for approximately 4 hours. When the pork is tender, pull it out of the slow cooker and allow it to cool slightly before using a fork to pull it apart.
Heat 3 tablespoons of olive oil in a large pan over high heat. Add the pork and fry in the oil until it has formed a slight crust. Serve with warm tortillas.