Sort and rinse cranberries. In a 2-quart sauce pan, combine cranberries and crushed pineapple with juice. Cover and cook over medium heat, stirring occasionally, until berries are soft and skins pop (about 10 to 15 minutes). Remove from heat; stir in orange marmalade and cinnamon until blended. Serve warm or chilled as a delicious accompaniment to turkey, chicken, ham, or pork roast.