Copyright is a form of protection grounded in the U.S. Constitution and granted by law for original works of authorship fixed in a tangible medium of expression. Copyright covers both published and unpublished works.
Copyright, a form of intellectual property law, protects original works of authorship including literary, dramatic, musical, and artistic works, such as poetry, novels, movies, songs, computer software, and architecture. Copyright does not protect facts, ideas, systems, or methods of operation, although it may protect the way these things are expressed. See Circular 1, Copyright Basics, section "What Works Are Protected."
When is MY work protected?
Your work is under copyright protection the moment it is created and fixed in a tangible form that it is perceptible either directly or with the aid of a machine or device. United States Copyright Office.
COPYRIGHT IN GENERAL Fundamental principles. Issues of ownership and fair use. Managing our copyrights, negotiating publication agreements, developing digital libraries, and posting materials to Web servers. Includes a series of podcasts. Columbia University.
COPYRIGHT and FAIR USE Overview of copyright with additional resources. Stanford University Libraries.
U.S. COPYRIGHT OFFICE Basic information, FAQs, and a site for teachers and students
Copyright's Highway: from Gutenburg to the Celestial Jukebox by 