In 3rd and 5th grades I am going into the classes to talk to the kids about internet safety, the Student AUP, and how to keep themselves safe online. We are using the PBS Kids-Digital Drivers License site to do this. (Note: This site has changed to Webanauts now).
This site is a perfect segue into talking to the kids about keeping their identity online private when gaming, emailing, chatting or on social networks. It also helps me to convey the importance of managing online usernames and password and to keep that information private, even for friends. This can be difficult in the upper ES and MS years for kids when peers can pressure them into giving out this information.
We go through the site together as a class and then discuss various points as we go. I also have the kids sign the SAS Student Acceptable Use Policy (See link above). This outlines the behaviors and expectations in regard to tech use at SAS.