Watch the Harmonics online guitar lesson by Mimi Fox from Flying Solo
This is a special technique that should be played VERY slowly to master. Harmonics add lots of color to what you are doing and break up the sound of plucked notes. I recommend OVER-USING harmonics in your playing for a while so that you can begin to really play them well. Russell Malone, Jody Fisher, and the late Lenny Breau all do cool things with harmonics that I urge you to check out. You'll see that my technique is completely different! Explore, maybe you will come up with your own way of doing them.