Brins>> thats what I was thinking, have a look at my post.
I know for a fact that there is a standard stereo jack plug for the input, (we had a fiesta on our recent trip to Spain, and we used it frequently), but I was curious as to whether there was some kind of adapter that allowed you to use USB that may go into an un-used port on the back of the unit. I have seen some iPod ones around, but they won't work with non-apple devices I don't think. They fit into the ISO connector on the back of the unit, commonly used for CD Changers.
The iPod kit on my mum's BMW mini connects in a similar way, and appears as a CD changer when there is an device connected to it. This allows you to control the track which is played, on the head unit, which is far more convenient. You also get the track titles appearing on the screen as well then.