I just copyrighted my Swish! bargello pattern. You can go to the U.S. Copyright Office website to get all the information. Here's the link:
http://www.copyright.gov/help/faq/
It is actually pretty simple to do. It costs $35.00. You fill out an online application, pay through a government place (alot like Paypal), and then submit pictures of your completed pattern and item. I applied 2 months ago and just got my Certificate of Copyright Saturday in the mail.
The application is actually pretty simple. There is a tute on it, explaining how to do it, and then it also explains every step along the way as you are doing it. I was nervous for nothing. Let me know if I can help you in any other way.
Good Luck!
Marilyn