Fourth-gen iPod nano owners can obtain the update by connecting their iPod to their computer, selecting the iPod from the left-side device list in iTunes, and then selecting the "Check for update" option.
Specifically, the 57.8MB update, labeled "iPod nano (4th generation) Software Version 1.0.3," delivers:
Support for Apple In-Ear Headphones with Remote and Mic
Support for Apple Earphones with Remote and Mic
Fixed instability issues when using Nike + iPod Sport Kit
Added a setting to turn off Cover Flow when rotating iPod nano and a Cover Flow menu item under the Music menu
When Shuffle setting is set to Songs, pressing play on a song in a saved Genius playlist will now follow the Shuffle setting
After playing a slideshow with TV out, Cover Flow album art is no longer distorted
Waking iPod nano after hibernating no longer distorts photos
Other minor bug fixes
Unfortunately, the two new Apple headphone options: the $79.00 Apple In-Ear Headphones with Remote and Mic, as well as the $29.00 Apple Earphones with Remote and Mic, have remained unavailable for purchase since their introduction alongside the new iPods in early September,
As is the case with the company new 24-inch LED Cinema Display, the Apple online store continues to list the accessories as "Coming Soon."