I believe we have opened up a delicious can of worms . . . plenty to know about on this very techinical topic. The "mail it to yourself" strategy as mentioned by wave22 is one way of establishing tangible form for a creation - this idea is discussed in the Wikipedia article (see, Copyright). It is a long article full of juicy info. Here is a part of it:
Obtaining and enforcing copyright
Typically, a work must meet minimal standards of originality in order to qualify for copyright, and the copyright expires after a set period of time (some jurisdictions may allow this to be extended). Different countries impose different tests, although generally the requirements are low; in the United Kingdom there has to be some 'skill, originality and work' which has gone into it. However, even fairly trivial amounts of these qualities are sufficient for determining whether a particular act of copying constitutes an infringement of the author's original expression. In Australia, it has been held that a single word is insufficient to comprise a copyright work.
In the United States, copyright has relatively recently been made automatic (in the style of the Berne Convention), which has had the effect of making it appear to be more like a property right. Thus, as with property, a copyright need not be granted or obtained through official registration with any government office. Once an idea has been reduced to tangible form, for example by securing it in a fixed medium (such as a drawing, sheet music, photograph, a videotape or a letter), the copyright holder is entitled to enforce his or her exclusive rights. However, while a copyright need not be officially registered for the copyright owner to begin exercising his exclusive rights, registration of works (where the laws of that jurisdiction provide for registration) does have benefits; it serves as prima facie evidence of a valid copyright and enables the copyright holder to seek statutory damages and attorney's fees (whereas in the USA, for instance, registering after an infringement only enables one to receive actual damages and lost profits). The original holder of the copyright may be the employer of the actual author rather than the author himself if the work is a "work for hire". Again, this principle is widespread; in English law the Copyright Designs and Patents Act 1988 provides that where a work in which copyright subsists is made by an employee in the course of that employment, the copyright is automatically assigned to the employer.
Copyrights are generally enforced by the holder in a civil law court, but there are also criminal infringement statutes. Criminal sanctions are generally aimed at serious counterfeiting activity, but are now becoming more commonplace as copyright collectives such as the RIAA are, more and more, targeting the file sharing home Internet user. Thus far however, these cases have usually been settled outside of court, with demands of payment of several thousand dollars accompanied by nothing more than a threat to sue the file sharer, which will be ruinous to many defendants in practice, thus such cases rarely make their way to civil law courts.
It is important to understand that absence of the copyright symbol does not mean that the work is not covered by copyright. The work once created from originality through 'mental labor' is instantaneously considered copyrighted to that person.
