I'm sympathetic to Robin on this one. For people who are interested in thinking seriously about these questions, I think a good first thing to do would be to run a search for metaethics on the stanford encylopedia of philosophy (http://plato.stanford.edu/). If people like that, then it might be good to buy a book that would serve as an introduction to metaethics, maybe an anthology, or a textbook. I'm not familiar with much of the literature, but I can say that Michael Smith's "The Moral Problem," serves as a pretty good introduction to a wide number of metaethical debates, though it's not written as an introductory book. I'm sure the bibliographies on the stanford encylopedia of philosophy articles would also be helpful.