Ok, I done this on the weekend with my alpine ipod adapter.
Unscrew three screws, two on the sides, one under the gear stick gaiter, pull the centre console towards you and twist it to the left.
If you look inside it, there is a lovely flat bit of plastic, just begging you to put it there...
Stick it down with double sided sticky pads, and if your feeling adventurous, a couple of screws. Then get a dremel, and chop out a hole in the top cubby hole of the centre console, just big enough for the cable to fit through (not the dock connector that plugs into the ipod, because everytime it slips down the hole you'll have to take the centre console out to fish it out...)
I took some pictures of it in situ, but not a picture of the back of the centre console

I'll get some pictures on Friday when I fit my central locking and sub.
I also (well my mate) fitted two 5 inch coaxial speakers in the sides of it and it looks proper cool...