Elmworth with their grade 3-9 students discussing just this. All of the material used can be found here where you are welcome to use it, modify it or drop me an email and I will move it over to your moodle course.
For the Grade 4-6's I suggested following up with a variety of websites on Internet safety and then use the Passport to the Internet as a culminating activity.
Thanks again to the staff at Elmworth for inviting me to their school and letting me borrow their students. It was an excellent day!