Sherri's blog on nurturing good character in your teen is an excellent outline on how to work with your teen to help him think through what he has been taught and the influences around him. She has described the many ways in which a parent can help lead a teen along the path of developing a good moral compass.
I find that talking to teens and working to help them think though important issues is vital. Another important way to help teens is to lead by example. Teens will often learn more by watching how we handle issues than listening to us tell them how to handle examples. I have heard more than one parent talk about their shock when they heard their teen cursing and learned that he is only repeating what he has heard them say in the past.
Think about the multiple exposures to adults in the media: rock stars, sports players, etc. who model poor behavior to our teens. Just this week Madonna in her endorsement for President Obama, stood on stage and cursed to such a degree that the rest of her content was almost not understandable. It is confusing to teens that such an icon can be cheered for such inappropriate behavior. So to say that our teens receive mixed messages in the examples around them is an understatement.
How can you help this confusion with your teens? STAY CONSISTENT in your behavior with your teens and be aware that your teen is watching you and everything you do. Show your teen that an adult can be respectful to others even if you disagree with others opinions. Think about your own religious values and how you should model them to your teen. Leading by example will give your teen a way to see that adults can have a strong moral compass related to their value systems.