"Moral Philosophy - a guide to ethical theory" by Jones, Cardinal and Hayward is an excellent description of the various ethical schools of thought and the objections to them, Chrisgel. I read Simon Blackburn's "Being Good" some while ago and remember having enjoyed it, but not (to my shame) so much so that I can offer a summary of it, so I'll have to read it again. Most recently (thanks to a recommendation on AB) I read Stephen Law's "The War for Children's Minds". This is a fine book. His purpose is to argue for liberal approaches to education rather than authoritarian ones, but in making his case he covers a lot of moral issues, and answers many of the criticisms of naturalistic ethical stances made by the religious. One of the main one of these is the accusation of moral relativism.
My own crude answer to your question "Where does morality come from?" is this: we evolved as herd animals and as such have no choice but to co-operate in order to survive. Further, as mammals we have a need to nurture young and this requires some degree of altruistic behaviour, call it mother love or whatever. The development of intelligent awareness allows us to reflect on our biological conditioning and to see its practical value to us. This rudimentary "morality" is in our early stages confined to the tribe. But it doesn't have to stay there. Increased intelligence gives us the ability to see things from others’ points of view, not only those inside the tribe, but those outside it as well. This intelligent reflection leads us to JTP’s (far more concise) answer – empathy. And empathy is that which creates the “ought” from the “is”.