If, like me, you have recently updated your iPhone to iOS 4.2.1 and have found that all of your iPod content has disappeared then you could follow the suggested method that involves re-syncing with itunes. However, if you are using your iPhone or iPod away from its iTunes connection then you might like to try this alternative solution that I found worked for me. I have only performed this on an iPhone but I suspect it will also work on an iPod.
The symptoms are that when you fire up the iPod app it displays the message “No Content”. Even if you purchase new content from the iTunes app nothing appears within the iPod app.
The solution that worked for me was:
1. Run the Setting app and select: General -> International -> Language and choose Francais.
2. Click Done. Don’t panic, but wait for the French “Changing Language” message to disappear and for the home screen to be redisplayed.
3. Start the iPod app and wait until its initial screen shows.
4. Return to the home screen and run the Settings app again (labeled in French as Reglages) and select: General -> International -> Langue and choose English.
5. Now fire up the iPod app and you should see that all of your content has been restored.