2nd bullet from the bottom
http://www.wireless.att.com/cell-phone-service/specials/iPhone.jsp
"Add a Consumer Data Plan for iPhone 3G to a qualified voice plan for $30 per month"
I also signed up for a family plan two days ago (will be "exchanging" my phone on the 11th, or whenever they get phones in). I was able to get either sms per line. you can do under that FAMILY plans if you sign up and then add options like insurance, SMS, etc., or get the unlimited for the family plan. The family share plans are considered "qualified voice plans"
As far as I know,...no insurance available on the iPhone.