Ok so I just went from a blackberry 8900 to the galaxy s4g and I love the world of android and am still learning ... So here's my question: with my blackberry I could plug it into the head unit in my car via usb cable to access the mp3s on the SD card. However, with the galaxy when I plug in the usb in my car it doesn't register and can't access my music. My head unit is new enough to be compatible with iphones, ipods, and blackberry. My tmobile rep said that it would work with my cars cd player and I'm wondering if there is something I'm doing wrong. HELP I miss my driving music!!