Finding Music: dealing with out of print and orphan works

Out of print and orphan works -- copyrighted works whose owners may be impossible to identify and locate -- present a big challenge to archivists, librarians, and creators. How much due diligence do archivists and creators need to do seeking out the correct owners? How can copyright owners protect their rights? Is there a better way to identify ownership to increase both the circulation of musical works and compensation for creators?