To establish a copyright you must simply print the following notice either on the cover or the page immediately following the cover of your book, report, etc. Here it is: 1981, John Doe, or Copyright 1981, John Doe.
Most people do not know that you are NOT required to register the copyright with the copyright officer, but if you DO wish to register it, write to them for the necessary application form. You then submit two copies of the publication along with the application form for each copyright.
For necessary forms and additional information, write: Register of Copyrights, Library of Congress, Washington, DC 20059.