So, you already have an iPod, and now you have just bought an iPhone and also an iPod nano. However, you realised that you can only have one library in your iTunes, and hope to create seperate libraries for different devices. Look no further, this function is just within iTunes, although Apple has not make it clear enough for the users to use this extra feature. So, all your need to do, is while you are launching iTunes 7 and above, just hold down the option key on your Mac (or shift key on Windows), you will then see a small pop-up window, giving the option to create a new library or choose the library you wanted to load. For iPhoto users, this is the same shortcut you would use if you wanted to manage multiple libraries in iPhoto.