In Michael Marshall Smith’s novel Spares, a disaffected cop decides to free human clones, kept for their body parts.
Although fiction, Smith’s book presents an interesting thought experiment and brings some salient questions to mind. For example, what would be the psychological effect of discovering that you had been cloned, or actually were a clone ?
With the science and ethics of cloning being debated widely in the media, ABC Radio National’s All in the Mind programme recruits a psychiatrist, a geneticist and an expert on ethics to discuss the possibilities.
Link to programme transcript.
Link to realaudio archive of radio programme.
Mind Hacks 
Another book on the same concept, by a better sci-fi author, Kiln People by David Brin.
His latest novel, and a very tasty one. ^_^