Does anyone use their Iphone to listen to IHeartRadio or WunderRadio? I like to use it at work to listen to different stations but it makes me wonder if my battery is ok. I have wifi turned off and 3g off so I am using EDGE and I am getting about 4.5 hours usage with 22% battery remaining. Does this seem right or should I hook up my iphone via USB while at work to save battery? This is my second 3gs as my first definetly had battery issues.