Electronic Device Privacy Act of 2008 - Prohibits any person acting under U.S. authority, derived from a sovereign's power to search at its border, from searching the electronic contents of a laptop computer or other similar device of a person entering the United States. Allows searches based on lawful authority other than a sovereign's power to search at its border. Defines "laptop computer or other similar device" to include any electronic device normally used for electronic mail or messaging or for storing electronic data.