The shoulder is the front leg and shoulder of the pig. It's a big hunk of meat, so it is usually sold broken into two large cuts. The top part of the shoulder is sold as a Boston butt or pork butt; the rest of it, the piece of the shoulder that includes the front leg, is sold as a picnic ham or picnic shoulder. The shoulder is one of the fattiest areas of the pig (the belly being the other). This means that the shoulder cuts are very forgiving for the cook: they may be cooked a long time without drying out. Their higher fat content gives them a particularly delicious flavor and luscious texture. They are also one of the least expensive cuts.
Shoulder cuts are delicious cooked with either dry or wet heat. They not only make excellent roasts, but shoulder is also your best choice for stews and braises. If you find steaks cut from the Boston butt, grab them — they will also be delicious cooked like a chop: grilled, broiled or sautéed. Boston butt, cut into cubes, makes great kebabs.