The Atheist Ethicist has been writing a nice series on morality and evolutionary ethics. Posts (so far) include:

• “Evolution Accounts for Morality?”
• “Concerning Evolution and Morality”
• “Evolution and Two Conceptions of Morality”
• “Evolution, Morality, and Objective Values”
• “The ‘Necessity’ of an Evolved Moral Sense”
• “Evolution, Altruism, and Morality”
• “Evolved Sentiments and Moral Content”
• “The Immorality of ‘An Evolutionary Basis for Morality’”
• “Evolution and ‘Descriptive Morality’”

Check them out!