Bumped thread, but what the heck, I missed it the first time around.
I just heard of what sounds like a fantastic book, I plan to order it soon:
Everything You Never Wanted Your Kids to Know About Sex (But Were Afraid They'd Ask) : The Secrets to Surviving Your Child's Sexual Development from Birth to the Teens. Despite the title, it is supposed to take an honest approach: "Acknowledging that kids are "inherently sexual" (male fetuses, for example, have erections in utero), the authors show how parents can influence their children's sexual development in healthy ways through honest communication."