When we took a marriage class at church, they actually recommended sleeping on arguments as a good problem solving strategy. The logic was that people think much more rationally in the mornings, and when you've had a few hours removed from the argument things seem clearer.
As for the original question, an apology is enough. Usually when I'm upset I need an hour to cool off and filter through the situation and figure out why I'm really upset (is it really the situation at hand? Or is it because it made me feel a certain way, struck a nerve with something from a former boyfriend or from my childhood, etc) After I've thought through the whole thing, we'll talk through it together using strategies learned in premarital counseling. So far, so good! We don't really argue that often.