Teaching ethics is hard and as the WSJ reports, colleges are not having an easy time of it.
CollegeJournal | MBA Track: "Three years after coming under attack for their M.B.A. graduates' involvement in the many corporate scandals, schools are still grappling with how to teach ethics more effectively."
How can you teach ethics? My best advice is to attempt to show why it really is in your best interests (i.e. think long term!) to act ethically and to show that the market is a harsh disciplinarian.
It would be interesting to see how many finance classes incorporate ethics. (if you know of any study on that, please send it along). My classes do discuss ethics, but not we do not devote an entire section to it, but rather bring it up whenever it seems appropriate. (for instance, dumping toxic wastes may seem a good short term solution, but in the long run, is really really stupid.)
Of course, the success of any ethics effort is debatable.