I'm certain they will work with both iPod and Powerbook/iBook power supplies, since they just replace the 2 flat pins in the adaptor, with the appropriate (for Italy, for example) 2 round pins. Having said that, I'm using a 2 Euro US->European Union adaptor that is rated for both 110 and 220 Volts, and have no problems. If you have the $39 laying around, and have to have a white adaptor, go for the Apple solution. Otherwise, you can find the appropriate adaptor at any larger store in Italy (Carrefour, etc.). Hope this helps.
Cheers