How to teach an artificial brain to understand right and wrong

Movies like I, Robot, Wall-e and Bicentennial Man pose interesting questions that blur lines between man and machines. They not only allow our imaginations to soar high but somewhere also peek a hint of fear or uncertainty about the actual good of our scientific actions when man tries to play God! However, with the latest developments in the AI sector it is safe to say, assassin robots or a trap of cyber-warp field like the Matrix, where they will enslave the creator of machines is still a distant and very unlikely future. Perhaps it helps us to understand our very humanness better when try to translate these traits of thought and decision-making into our machinist creations! So, how far are we from having robot with morals?