A creative work is protected by copyright from the moment the work assumes a tangible form – which in copyright circles means as soon as the work is “fixed in a tangible means of expression.” You don’t have to put a notice on the work – or register it with the US Copyright Office in Washington to get protection – although there are some benefits to doing these things if you are creating a major work.
So, as soon as I post this article to “The Bloggers’ Bulletin” the copyright to the work is done and I, as the author, have the right to stop others from copying my work.
If another blogger copies my work and posts it to his blog as his own, he or she would be liable to me for copyright infringement.
If I want statutory damages in the US (damages set by a statute rather than what I can prove I lost), I need to prove that the infringer knew what he was doing, that is, that this was not an “innocent” infringement. This is easier to prove if I use the standard copyright notice. The usual notice is (c) year of publication, author, or, in this case (c) 2010 Nils Montan.
If I want to sue the infringer in the US, I have to register my work with the US Copyright Office. The Office has a very helpful website with a lot of information plus the forms you will need to register your work at http://www.copyright.gov.
Unless you are creating the work for an employer within the course and scope of your employment, or unless you have been commissioned to create the work under contract, or unless you assign the work, you, as the author of the work, are the copyright owner and entitled to all the rights under the law of copyright.
Copyright protection around the world are fairly similar due to the Berne Convention, under which member countries must afford copyright protection to authors who are nationals of any member country. The Berne Convention allows US authors to enforce their copyrights in most countries and allows the nationals of those countries to enforce their copyrights in the US.