I hadn't really considered teaching this, but one could use the ACM Code of Ethics and Professional Conduct, and simply talk through the major points. I looked at the General Moral Imperatives section and it basically boils down to the usual ideas about "doing what you would want to happen" in a situation. If people do not realize that we are in a collective enterprise and that their actions affect everyone, then they need more basic education.
To answer your questions: There is some "soft skills" training here, but I am not involved in presenting it. As far as I know, it is not discussed otherwise and the students are not required to accept any set of principles. I guess we figure that they already have it. My co-instructor referred to ethics as "the things we used to assume everyone already knew." Where and how they used to learn it and who is failing in their responsibility, I do not know.
Gerald M. Weinberg writes about The Platinum Rule (do unto others as they would be done unto) and I can't see that much more needs to be said about ethics, beyond illustrating what could happen if that rule is not followed. It is no different from other fields that have codes of ethics and professionalism. (Except that we can easily influence the lives of millions of people, for good or ill.)
In this reference - Stanford panel debates: Does teaching ethics do any good? - they ask, "can something as personal as ethics be taught in a classroom?" I don't see ethics as personal, any more than physics or finance are. If you know what to do, you can safely assume that any other person who also knows will do the same thing. The only 'personal' factor would be ignorance.
It also says, "teaching students social psychology, rather than moral philosophy, is one of the most effective ways to make them more responsible social actors." I would agree. Finally, one participant said, "When I teach them how to write a philosophy paper, I definitely assume I know better than they do how to write a philosophy paper ... [but] I'm 100 percent certain I am not more virtuous than many of my students. Some of them live much more conscientiously than I do." I don't understand that either: why wouldn't more experience make one more virtuous? As the old saying goes, good judgement comes from experience and experience comes from bad judgment. Shouldn't this be true in all cases?