This week Apple has officially made public a recall program for its original iPod nano model here in the USA citing a rare overheating problem that has recently posed enough of a risk that full replacements will be offered on the whole generation. This isn't the first iPod nano 1st generation recall on earth, but it is the first inside the USA. Apple is recommending that users discontinue using their devices immediately and follow along with one of the methods they've got available for replacing the device with another model for free from Apple.
This issue is, again, a battery issue, and does not affect any other model iPod or iPod nano from any generation. You've got a couple of options as far as replacing your model with Apple, the first being online with Apple's [replacement form.] You'll notice a list of countries that you'll be able to get the recall in, including Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Ireland, Italy, Japan, Luxembourg, Netherlands, New Zealand, Norway, Spain, Sweden, Switzerland, United Kingdom, and now the United States as well.
You'll need your iPod nano's serial number to find if your device is eligible for the replacement, this number able to be found as indicated in the image above, right there on the back of the device. If you've got a personalized unit, note that you won't get a personalized replacement unit, and by all indications you WILL have to hand over your old unit if you want a new one. If you do not want to use the online form, you can visit your local Apple store or Apple Authorized Service Provider with your unit in question for validation and the trade-up.
All replacement units will be "warranted to be free from defects for 90 days from the date of service," this assured by Apple.