This is nothing fancy... but thought I'd post anyway.
I installed a USA Spec PA11–HON2y iPod kit which I modified. What I really like about this kit is that I was able to keep my in-dash CD changer as well as XM radio.
One thing that concerned me was that a change from "playlist", "direct" or auxiliary mode required a change to dip switches on the unit. I didn't want to install it in the glovebox and there really was no good place to put it where I could easily change the configuration. I ended up sticking it to the left of the gear shift.
So I decided to modify the unit and setup switches I got at radio shack so I could adjust the configuration easily. I used a dremel, some wire and soldering iron. Basically I just "extended" the two dip switches so I could reach them (and the auxiliary inputs) via the center console.
Originally I used this setup with an iPod 3G but am happy to report it also works with an iPhone. The iPhone complains that the adapter isn't made for it but it seems to work just fine.