There are a number of online games that are fun and teach media literacy - online safety, false advertising and cyberbulling.
Games for older students:
Media Awarness Network Games
On Guard Online
A collection of games for students of all ages.
Google's Cybersafety Games
From the Open Directory Project
Online Safety for Younger Students
Bad Guy Patrol
Benson Village School also has a publication from On Guard Online titled
Net Cetera: Chatting with Kids About Being Online which 7th and 8th grade students have been reading.