I think being an example of what you expect from your kids is the one sure fire way of instilling morals. They're not born knowing right from wrong but you can sure show them the right path whether they take it or not. Also, a child has pretty well formed a basic personality by three years old so start as soon as you can.
This all goes with a caveat. Not all children are alike and what works with one may not work with another. All four of my Grandsons are as different as night and day. If you want a Lyle and Eric Menendez, give them everything they could possibly want (not need) just to get them out of your and your wife's hair.
“War is an ugly thing but not the ugliest of things; the decayed and degraded state of moral and patriotic feelings which thinks that nothing is worth war is much worse.” —John Stuart Mill