Melt butter or margarine in a 1-quart saucepan over low heat.  Stir saltine crumbs into hot melted butter. Arrange half the saltine mixture in a 10-by-6-inch baking dish. Top with oysters. In a small bowl, mix the half & half, salt and Worcestershire sauce. Pour over oysters. Sprinkle oysters with half of parsley. Sprinkle with remaining half of saltine mixture. Top with remaining parsley. Bake at 400 F  for 20 to 25 minutes, until lightly browned and bubbly.