Gosh, I remember when
KYW (note the K callsign) in Philadelphia, PA went to AM Stereo.
I never did understand what all the hype was about. They are an all-news station
There is plenty of AM in use here in Northern NJ. Until I put Cat-5 in at home, the RF interference was louder than the other party asking "Do you have the radio on?"
Have a look at the US stations via:
http://svartifoss2.fcc.gov/reports/state_rs.cfm