US Government Publishing Office
Ben's Guide to u.s. Government: Songs and Oaths: The Pledge of Allegiance (3 5)
Includes the words to the Pledge of Allegiance with accompanying facts about its history and code of rules that is appropriate for younger students.
Other
Us flag.org: Flag Etiquette
This website teaches how to properly treat your flag. It details what to do and what not to do with your flag. It also explains how to display the flag outdoors.