Aux. Input?
 

I've been driving around in my new titanium 5 door Mazda3 and I've been loving life. My biggest compliant about this car (it's a bit of a stretch, I know) is that it doesn't have an auxiliary input or tape deck! The car came with a great AM/FM/single CD player, but I'm wondering if there's a way to hook my mp3 player up to the stereo without having to use an FM transmitter. I've noticed that the stereo has a MD/Tape mode that is not in use and I'm guessing that there's an extra input not being used by the system somewhere behind the dash. Any suggestions on how to go about using this input? Is this even possible?