If the dock is a straight line out with no DAC in it, then yes. For instance, the iPhone dock that came with the original 2G iPhone works fine. But if you're using the Apple Universal docks that are being sold a few years back up until now, these have the remote control that lets you control the iPod's volume... these have a separate DAC or maybe some kind of other cricuitry inside that isn't pure lineout, these don't work with the iDo. Incidentally, these docks also sound horrible.
And yes, the 2G Nano works.
It's the oldest model that will work with the iDo and similar products. The Nano 1G to my knowledge does not (have not tried). Things like the iPod 5G do not. You need to go up to the iPod Classics.
