The Constitution:
http://www.constitutionfacts.com/us-constitution-amendments/fascinating-facts/
http://www.history.org/kids/games/constitution/
www.usconstitution.net/constkids4.html
http://www.scholastic.com/browse/collection.jsp?id=391
http://www.scholastic.com/content/collateral_resources/pdf/a/Abota_Const_Factsheet.pdf
www.socialstudiesforkids.com/subjects/constitution.htm
http://teachinghistory.org/spotlight/constitution-day
http://www.archives.gov/exhibits/charters/constitution.html
The Bill of Rights:
http://www.historyforkids.org/learn/northamerica/after1500/government/billofrights.htm
http://www.history.org/kids/games/rights/
http://www.archives.gov/exhibits/charters/bill_of_rights.html
Amendments:
http://www.scholastic.com/content/collateral_resources/pdf/a/abota_stu_repro_6.pdf
http://www.ducksters.com/history/us_constitution_amendments.php