Newseum also has lesson plans and cool anchor charts to display in your classroom--all available for free once you register.
Another source for teaching media literacy--and especially online media literacy--is the Stanford History Education Group (SHEG)'s latest website, "Civic Reasoning Online." You can read my longer summary of the site, and other reasons to love SHEG in this earlier post. Or go directly to their website and register for free access to their material. You won't be sorry.