Today has been my busiest day with the iphone. Lots of calls and emails, etc. Today I needed to conference call with somebody so I attempted to use the add call feature. When I moved iphone away from my face the buttons were unuseable for a solid 20 seconds. Totally unresponsive. I didn't think anything about it until a while later I was on the phone and had another phone call come in. I couldn't answer that call either for about 20 seconds. I THINK that maybe the screen is too warm from being against my face or something that makes the iphone unuseable. I've done some 'controlled' experiments' and found this to be true in every call I have made. Anybody else??