I wrote a post -- "Teaching Your Kids About Sex" for a blogging friend that had a month focusing on The Proclamation of the Family. I took one of the difficult titles, because I love a challenge, and also because my kids are now 30, 28, 25, 22, and 16. So I have some history. You can read it here.
Jocelyn at "We Talk of Christ, We Rejoice in Christ" just recently posted her FHE idea, going over the book I had recommended, with her children. Some people may not be comfortable teaching their kids before kindergarten, but we both agreed, that we wanted our kids to hear it from us, first. I didn't want my kids to hear about the birds and bees at school or from friends before they heard it from me. She also had this great lesson that I have included here: