Register your work with the U.S. Copyright Office. Copyright registration serves as proof of authorship. It is also necessary if you take legal action for copyright infringement. In addition, U.S. Copyright Office registration lasts for 50 years and is renewable for 25 more years. Other registration services such as the Writer's Guild of America provide only proof of authorship, and require you to renew within five years. So whether you use other services or not, you should always officially register your work with the U.S. Copyright Office.
The U.S. Copyright Office currently requires 3 things to register a work:
A clean, single-sided, unbound copy of the work.
A correctly completed form PA, with necessary spaces filled in and signed in space 8.
A check or money order for US $20.00, made out to the Register of Copyrights.
The materials should be mailed to:
Register of Copyrights
U.S. Copyright Office
Washington DC, 20559
You should send your registration materials by certified mail. Keep a copy of the filled-in form, your work and the certified mail receipts. If the materials are in order, the Copyright Office will send you a confirmation in the mail several weeks later. Registration is valid from the date the Copyright Office receives your materials.
U.S. Copyright Office Form PA is for registering dramatic works (plays, screenplays). It is available from the U.S. Copyright Office and from the Office's web site in Acrobat (.pdf) versions. The Copyright Office accepts photocopies of Form PA, but may not accept non-standard size or dot-matrix printouts.