MB has an internal microphone right? Well if this is true, why doesn't my microphone work when having an iChat Cam conference? I can hear the person on the other side, but when I go to talk, they can't hear me. I looked at my microphone settings, and everything is working/enabled/etc. Am I overlooking something? or Should I take my MB to the Apple store after the holidays to have someone look at it? Thanks! Happy Holidays and Merry X-Mas!