Hi, you can only use your iPod on one computer at the same time a Mac or a PC and not on both at the same time, you can use your iPod on your PC for now but you will need to reformat it if you want to use it on your Mac, you will loose all songs on your iPod.You should only use the iPod on your Mac once you receive it and not on the PC, the PC can't read the Mac formatted iPod so you can't use it as an external firewire drive either, but the Mac can read the PC formatted iPod so you can use it as an firewire drive, you will notice a lot of strange files and folders but it should work for most files. What I would do is, use your iPod on your PC for now and erase all songs from your iPod once you receive your mac, then use the iPod as an external firewire drive on your PC and copy all your songs to the drive ( you won't be able to listen to them on your iPod ), connect the iPod to your mac and copy all songs from the firewire drive to your hard drive, import them into iTunes, reformat and sync the iPod. You can use your iPod on either the PC or the Mac but I would go for the mac for several reasons, iTunes for mac is much better than the windows version, there are a lot of cool apps that work with the iPod and iTunes ( iSync, iCal, 3rd party apps, ... ), better integration in the finder..... I hope this text is not too confusing
