I got my first ipod in December as a birthday gift, and the time only had an Acer (ugh) laptop, so I downloaded itunes and used my nano with Windows. I just bought a MB this month and got an ipod touch as well - the ipod touch has only been used with my mac and although the nano works on my MB, it says "only Mac formatted ipods can be updated." Is it possible to reformat my nano for my mac so that I can update the software if need be? I no longer use my Windows laptop with my ipods anyway. Thanks!