You can download a very comprehensive answer from the Internet. Terry
 Carroll posts a six-part Copyright FAQ to misc.legal, news.answers and
 other groups. A short answer follows, not based on that article.

 Disclaimer: I am not a lawyer, and this is not legal advice. Also, there
 are very likely to be differences in copyright law among nations. No
 matter where you live, if significant money may be involved, get legal
 advice. The following is adapted (and greatly condensed) from chapter 4
 of the Chicago Manual of Style (13th edition, ISBN 0-226- 10390-0).

 In the U.S. (at least), when you write something, you own the copyright.
 (The exception that matters most to programmers is "works made for
 hire", i.e., code you write because your employer or client pays you to.
 A contract, agreed in advance, can vest the copyright in the programmer
 even if an employee; otherwise the employer owns the copyright.) You
 don't have to register the work with the Copyright Office unless (until)
 the copyright is infringed and you intend to bring suit; however, it is
 easier to recover damages in court if you did register the work within
 three months of publication.

 From paragraph 4.16 of the Chicago Manual: "... the [copyright] notice
 consists of three parts: (1) the symbol [C-in-a-circle] (preferred
 because it also suits the requirements of the Universal Copyright
 Convention), the word 'Copyright', or the abbreviation 'Copr.', (2) the
 year of first publication, and (3) the name of the copyright owner. Most
 publishers also add the phrase 'All rights reserved' because it affords
 some protection in Central and South American countries...."

 Surprise: "(C)" is legally not the same as the C-in-a- circle, so those
 of us who are ASCII-bound must use the word or the abbreviation.