Mailing it to yourself and keeping it unopened is a good step, but if you end up in court it really is imperative that it be officially registered. It will improve your chances in court significantly. Assuming we are talking US Copyright, I believe it costs $50 to copyright something. At $50 a crack, I can see why so few people bother who do lots of little things, but perhaps there is different scale for small items (like poems, digital art, short stories, etc.). In theory, if you created it you automatically hold the copyright to it. But if you think your work has even a slight chance to making it to a series, by all means do a formal registration. jon

 
~jon
My Blog - Mad Utopia Writing in a new era.