CI1 Computer Output?

I have a macbook pro 10.6 and I was just wondering why the output from my computer does not do through to the CI1 via USB and in turn into my headphones. Can anybody help?

In your software or itunes and the internet? This reminds me, I need to use my CI1 with youtube and Windows Media Player. :bulb:

I had problems hearing audio from youtube, and general audio from computer, but turned out it was a driver issue, the version on the disc that came with the interface was outdated, thanks though!