I received this post via a coworker here at Cessna, so I wanted to give you an answer in case you still needed one.
First, this is a great link. It should answer all of your questions, plus some more information that may be helpful. http://www.avweb.com/news/pilotlounge/182653-1.html
Some extra points:
1. As far as hearing protection for babies, what I find works best is a head sweatband. If you put the sweatband around the baby’s head to where it’s across the forehead and covering the ears, it stays on and seems to reduce noise very well. No baby has ever objected that I’ve seen. If you want to be a little more careful, put cotton balls on the child’s ears and put the sweatband over them.
2. There is no problem putting a child in the front seat. I personally would honestly encourage it. It gives them a chance to be interactive with flying and they are less likely to be sick that way. I was flying in the front seat from time to time since I was 2.
I hope this helps!