Good references when looking to see if someone really legally owns a name, copyright, etc.
Copyrights = http://cocatalog.loc.gov/
Trademarks = http://tess2.uspto.gov
Patents = http://patft.uspto.gov/
Website Address = http://www.internic.net/whois.html
Copyright, a form of intellectual property law, protects original works of authorship including literary, dramatic, musical, and artistic works, such as poetry, novels, movies, songs, computer software, and architecture. Copyright does not protect facts, ideas, systems, or methods of operation, although it may protect the way these things are expressed.
A trademark protects words, phrases, symbols, or designs identifying the source of the goods or services of one party and distinguishing them from those of others.
Patents Set of exclusive rights to an inventor for a limited period of time in exchange for a public disclosure of an invention.
Website Address (aka "Domain name") The core portion of a website name (such as "apple.com" or "msn.com") of a web site, which is uniquely registered to an individual or company (also found to the right of the @ sign in an email address such as "firstname.lastname@example.org".)
Side note #1. LLC Company Names appear to be registered and maintained by state only. If you want to reserve a LLC name nation wide, you may have to register with each state.
Side note #2. The copyright office's FAQ has a question called "How do I protect my sighting of Elvis?". No kidding. Check it out. http://www.copyright.gov/help/faq/