This source is pretty self explanatory. It is a website solely dedicated to the subject and gives great information on the subject. This website also gives other resources and does a great job outlining the nine elements of the subject.
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 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.
This is a website helping define the issues of appropriate technology use. It provides a framework of nine elements for users to better understand the issues.
This website is great because it gives options for PD and links to blogs and worksheets, and toolkits to integrate Digital Citizenship into the schools we work in.