The U.S. Copyright office is considering changing the copyright laws regarding "orphan works", (or works that it is impossible to contact the author for permission to use).
OrphanWorks.org is asking for comments from people who have
had problems trying to clear a potentially
copyrighted
work -- either for a new creative effort or simply to make the
work available to the public again. If you have ever dealt with an issue like this, or you are an artist who's work might one day be considered an "orphan work" it's essential you make your voice heard.
This webpage looks like it's something every artist needs to seriously consider.