Without having read any book or opinion on the issue, I have to say that morality is a subjective concept that when you strip it of all its subjectivity what you have left is guidelines for collaboration among humans to improve our survival rate. Human evolution at its best... or worst. Time will tell
Morality from God???
We humans created God... and He created morality... Therefore we, humans, are the source of morality. Problem solved. Fear not my child.
EDIT
Simon, you stole my thunder, and I am glad:
we create him in our image rather than the other way around. Which is probably why he's usually such a jerk.
Truer words had never been spoken before