The latest iPods have a cryptographic "checksum" in their song databases that prevents third-party applications from synching with the portable music players. This means that iPods can no longer be used with operating systems where iTunes doesn't exist -- like Linux, where gtkpod and Amarok are common free tools used by iPod owners to load their players. If you buy such an iPod, you're only option to upload songs is to use Wine + iTunes or, more drastically, iPodLinux.