I wanted to figure out a nice clean non invasive way to mount my iphone for use in my new Altima. The solution I came up with uses a combination of the Ped3 Form holder on a Naja King Coil stand both from Thoughtout.biz. You can watch how I put it all together on the video I made. I do also use the Belkin retractable stereo cable for feeding the audio into the aux of the Altima stereo system. It keeps the whole rig easy to remove and get out of the way.

Thoughtout.biz Form
http://thoughtout.biz/FORM

Thoughtout.biz Naja
http://thoughtout.biz/NAJA

Belkin Retractable Stereo Cable
http://catalog.belkin.com/IWCatProductPage.process?Product_Id=377115

* Update Aug 6, 2011 *

I also have this device in my older Altima.  Because the built in handsfree bluetooth does not support A2DP for audio playback the TuneLink Auto works AWESOME!  It lets my iPhone4 stream podcasts, audiobooks, pandora etc to my car audio but still uses the built in handsfree of the Altima for phone calls.  It seamlessly transitions between the two.
http://www.newpotatotech.com/TUNELINK_AUTO/tunelink_auto.html