the Apple brand ipod charger is outrageously expensive. i bought my 1st gen nano from a friend for $50, the Apple usb charger is $39.99. to make this unit, i will show you how to take apart a dc wall adapter without ruining it.
Step 1: opening the wall wort
opening these can be quite difficult. i found that cutting of the cord at the base and prying the case apart is the easiest method.
I used a chisel to slice the cord at its base, no damage to the case.
As you can see in the photos the chisel is facing away from the plastic so it doesn't gouge it.