Following the launch of the iPod nano replacement program in November 2011, there is apparently a bit of a backlog in fulfilling requests for new devices due to the popularity of the program. We have checked with Apple support in the UK and the US and, while there was initially a six week lay period between the time that Apple receives the iPod and the time that a new one has been sent out, this is now apparently closer to eight-ten weeks. In addition, anecdotal reports on the Apple support site tell similar stories, although there are exceptions with the odd person receiving a new device within four weeks.
The replacement program is designed for some first generation iPod nano owners who have devices that may be susceptible to battery overheating. As such, Apple has offered to replace the affected units and, as of last month, has actually sent out new sixth generation iPod nano units instead of replacement first generation iPods. Judging from comments on the Apple support pages, it seems that this is now a common occurrence.
If you haven’t done so already, you can check if your first generation iPod nano meets the criteria for replacement by entering the serial number of the device at Apple’s webpage for the replacement program. You aren’t guaranteed to receive a sixth gen iPod nano, but can at least get your faulty device replaced (although it may take a little while).