If the Audio In takes a standard 3.5mm headphone jack, then all you will need for the iPod or the Zune is a male-to-male, 3.5mm headphone cable like this one:
http://www.amazon.com/Cables-Unlimit...2878884&sr=8-1
I don't know about Pandora streaming through the Zune.
ETA: On second thought, for the iPod, this cable would be better: http://www.amazon.com/Cables-Go-3550...2878973&sr=1-1
That will provide better sound quality than the 3.5mm to 3.5mm cable. If you care about such things.