I have now had a wide range of experience being trained to lead internet safety discussions - I had the iSafe training, I worked with Parry Aftab (Wired Safety) and have all the materials from NetSmartz. I give talks to many local schools, both to students and parents.
My most recent evolution of "the talk" was quite different. I invited my own children, both high school students, to come along. We did a two hour workshop called "Anytime Anywhere Socializing". They ran the discussion - their goal was to help parents understand that, while there are known dangers on the internet that kids should be aware of and careful about, social networking is now an essential part of the teen experience. Their mission was to convince parents to relax and participate, but not be too overbearing. It was a fascinating evening, to be sure!
What are others doing along these lines?