I have had my iPhone 3G for about a month now. It works great except for the part where a few days ago it lost its sound. Whenever someone calls me or I call them, I don't hear it ringing nor do I hear them talking. They can hear me just fine, though. I've tried the headphone trick and plugged/unplugged it multiple times. I've blown in the headphone jack and I made sure nothing was on mute.