This is a short and sweet little overview of what a digital footprint is (aimed at younger children). This is helpful with teaching digital citizenship since students need to learn that everything they do online is permanent and is basically public.
This Prezi explains what it means to be a good digital citizen. This would be great to help explain digital citizenship to students in a more visual way.
This is a GREAT website for teachers of ALL ages. It provides lesson plans (PDF and online versions), interactive games, classroom posters, and numerous other teaching tools for teaching students about Digital Citizenship. It also has these tools for other topics like EdTech and Professional Development.
This article speaks towards California's department of education and how they are trying to implement new educational ways to tell students about digital citizenship. This is important because technology is becoming much more prominent in today's education.