Philosopher (and friend) Massimo Pigliucci recently concluded a series of seven essays about ethics on at his blog Rationally Speaking. In these seven essays, Pigliucci discusses everything from meta-ethics (is there right and wrong?) to ethical theories (what is right and wrong?) that are person-focused in nature (deontology, virtue ethics) to ones that are more societal or political (consequentialism, egalitarianism). 

Here is a list of the entries and their subject matter. I highly recommend them as reading for anyone interested in exploring the basic of ethics.