Research in moral psychology has often been done either primarily from the armchair (consider Nagel, Smith, Korsgaard, etc.) or primarily in reference to empirical work (consider Kohlberg, Batson, Damasio, etc.). But a hope I share with many others is to continue the trend of blurring these into a thoroughly interdisciplinary approach.
Partly toward that goal, I've completed a draft of a relatively short entry for the Routledge Encyclopedia of Philosophy entitled "Empirical Work in Moral Psychology" (PDF). It covers both x-phi as well as empirical work not done by philosophers, and it ties them to traditional debates in philosophical moral psychology. The condensed range of topics included are: free will and moral responsibility, egoism and altruism, moral judgment and motivation, weakness and strength of will, and moral judgment and intuitions. The article is meant as a short introduction to this burgeoning field while following closely to the topics that appear in Michael Slote's REP entry "Moral Psychology."
Any feedback would be great, either in the comments thread or via email (joshdmay at gmail). Of course, if I've made a shameful error, feel free to let me know privately! I throw this initial draft out there only because I hope input will make it the best resource it can be. There are many constraints on this particular piece, so I certainly cannot accomodate all feedback. But I'll do what I can.