Careful! Your 1st Generation iPod Nano May Overheat!

"Apple has begun a new replacement program for some of its first-generation iPod Nano units, which, the company says, contain batteries that can overheat."

Batteries in units sold between September 2005 and December 2006 pose a possible threat as they could overheat. The problem is with the battery apparently, and if you have one of the units (find out by going here) you can get a free replacement. The details are outlined here.