I have changed the standard stereo in my car to an Alpine one. Perfect for Ipods. (Cable plugs into the back and run it to your glove box and plug in the Ipod) The ipod is controlled directly from the headunit itself so no need to touch the ipod again once its in the glove box. The ipod also charges when the stereo is on.
Before I had the Alpine I had a Kenwood for a few weeks. On the kenwood it had a USB port so I just used a memory stick with all my music on and that was also controlled through the headunit. But I found the unit itself to be fairly fiddly and I was always changing albums instead of tracks. I could also connect an mp3 player to this unit.
You can get the Adapter ,taking it from a the current double din size to a single din, from Car Audio Security as izikog has posted, although this is the autoleads one. My autoleads one looks a bit cheap and is not a very good fit so i think it is worth paying the extra and getting one from ford.
My headunit with autoleads facia adapter

Old Kenwood. You can see from this pic that the facia isn't a good fit.
