Thanks for the guide, I successfully replaced the battery of my iPod Nano 2! A couple of points:
- don't even think of starting the project without a #000 Philips screwdriver, no a #00 one won't work and will only strip your tiny tiny screws.
- I concur with people suggesting that it's much easier to de-solder and re-solder the leads from the battery terminal, instead of the very hairy process of doing it from the iPod circuit board. You will need to cut open a bit of the plastic wrapping of the battery to expose the terminals (and needed to remove some gunk covering the terminals of the original battery), but it's much easier than messing with the iPod circuit board.
Good Luck! :)