I know there's no 3.5mm jack for this, but I just looked up the pinout of the iPod dock, and pins 5 and 6 would be used for right and left audio in. Thinkin' about makin an adapter coupled with a future Audacity app would be great
http://pinouts.ru/PortableDevices/ipod_pinout.shtml
http://pinouts.ru/PortableDevices/ipod_pinout.shtml