If it was an iPod touch and he set up the Find My iPod service prior to the iPod going missing, then there is a chance that can be tracked, though it depends on a number of factors (the iPod is turned on, connected to a WiFi network, and has not had the Find My iPod service disabled). He can log into icloud.com and go to the Find My iPhone section. Note, though, that he'll only get the location of the WiFi router to which the iPod is connected; there's no way to pinpoint the exact location of the iPod itself.
If he did not set up Find My iPod or it's not an iPod touch, then there is no way to track it. He'll need to notify the police and change any passwords for any online accounts he may have used from his iPod (the iTunes Store, for instance).
Call the cops?
If you have iCloud for your device and on your computer and the Find My iPhone app you should be able to locate it from a different iOS device. If the device was restored, you cant do anything. Reset any passwords used on that device (ei. Facebook, email, Twitter, etc.....) and yes call the cops, Apple won't do anything. To be able to get your serial number go to