Copyrights apply to original works of authorship in any medium. Copyright protection gives the owner of the copyright an exclusive right in that product. It applies to literary works, musical works, dramatic works, pictorial works, architectural works, and software.
Copyrights are obtained by registering with the U.S. Copyright Office. If granted, the copyright is created when the work is completed.
One important thing to remember about copyrights is that they do not protect the idea. They only protect the expression of the idea. Thus, you can get a copyright on the great American novel once you finish it, but you can't protect the concept that exists in your head for what will be in it.