Anything that is fixed in a tangible medium is copyrighted (i.e., anything that is in written form, or that can be performed, videotaped, put on the Internet, photographed, drawn, etc.) Examples of "Copyrightable Works" include, but are not limited to:
- Works of literature
- Computer databases and software
Another way of looking at it is that patents protect ideas, but copyrights protect the expression of ideas. Generally speaking, a copyright prevents someone else from copying your work.
Copyright protection begins, automatically, the moment the work is created. Even though notices are no longer required by law, it is a good idea to place a notice (year, author/owner) on the work to give notice to potential infringers. Otherwise, infringement may take place with the claim that it was assumed no copyright was in effect (since there was no notice).
Copyrights do not need to be registered, but if the potential value of the copyright is such that legal action against infringements is likely, a registered copyright (with the U.S. Copyright Office) will allow recovery of statutory damages of up to $20,000 for nonwillful infringement and up to $100,000 for willful infringement. Registration is simply a matter of filling out a disclosure form and sending it (along with a small fee payment) to the U.S. Copyright Office.
A copyright allows the owner to control the replication and use of the work. For copyrights owned by the author/creator, the copyright lasts for his or her life, plus 70 years. For works for hire, anonymous, or pseudonymous works, the life of a copyright is 95 years from the year of publication or 120 years from the year of creation, whichever expires earlier.
For a detailed discussion, visit this site: Copyright Basics (Copyright Office, Library of Congress)