Own an iPod Nano 1st generation device? These went on sale late 2005 through 2006. Apple are WARNING that YOU SHOULD STOP USING IT due to a "very rare" battery overheating problem. What is impressive is that Apple is giving free replacement of the affected models, as verified by the serial number. This applies globally.
For further information, and to register your Nano for replacement, see http://www.apple.com/support/ipodnano_replacement/