I just installed the spec.dock iPod adapter in my 2008 with navi. I have one of thes in another car and love it. IMHO, it is the best way to go to get a extremely clean and nice looking mounting option, but it is a bit pricey. I have an iPhone, so the only controls I have from the stock system are track forward/back and fast forward/rewind, but that is all I wanted. Regular iPods have the ablilty to select up to 6 playlists from the radio control.
http://2point5.com/
Here is a link to some pictures
http://www.box.net/shared/a1ekgjzk8o