My wife, my two older children, my younger brother and two friends (my 5 year old is too young to be trusted with that knowledge yet and I never let him see me put the gun on). That's it. Also, when I chaperone other kids (i.e. my daughter's friend comes to a movie, or 3 or 4 kids come with my son and I to youth sports camps) - my kids are under strict orders from my wife and I to NEVER tell their friends that mom and dad carry. Most of my friends would probably be ok with it but I don't need the hassle of dealing with so many parental viewpoints.
These days, you can get into a verbal fight for eating meat in front of some kids so we have a don't ask, don't tell policy. My wife doesn't actually CARRY her pistol (which annoys the crap out of me, but she's firm about that one and gets angry when I ninja it into her purse when we go out) but keeps it in her glove compartment in her car. I am hoping that changes when our youngest one gets older.