Air Play worked just fine with my 3GS for years. When I got my 4S using Air Play would take down my whole network (both Extreme & Express routers). I bought my Airport extreme less then 1 year ago. After multiple calls to Apple Care and spending 3 hrs on the phone It was suggested that I go to the genius desk with all the devices. At the Genius Desk I was told that I needed a new Airport Express. I bought one an installed it. Now the same thing happens again. My Airport Express sometimes doesn't seem to be on and I cannot see it using the Airport Utility - although the green light is on. I power cycle it and it comes back up. I called back to Apple Care and they told me to go to the Apple Store for a free replacement (less then 1 year old & under warranty). Upgraded my iPhone to V 5.0.1 and installed the new Extreme - same thing happens. I also have replaced my cable modem from Time Warner. I'm at a loss at this point. :-( Anyone else experiencing these problems with the 4S?