I plugged a DirectTV feed into my mic port. It records beautifully in FCP, but the only time I can hear it is by playing back what I recorded. I want to monitor it and cannot get a signal that will line-out through the headphone output. My headphone line-out works fine with any other mac sound. Is their a setting I need to turn on?

I wonder if you would have better luck with software designed to be primarily for recording? Anybody know of some good freeware for the Mac? Maybe Audacity?

I have soundtrack pro, but still can't get it to work. The odd thing is that I both see the level and can record the sound for playback. I just can't monitor it in real-time.

Well, if you incorporate an analog mixer and calibrate it to your computer, you can monitor on the mixer and be reasonably sure of success. It will add other benefits as well.