Today I installed iTunes (Windows installer) via wine. But after installation it didn't work.
Then I installed iTunes (Windows installer, too) in Windows 7 in virtualbox. But it can't read the iPod via USB port.
People said you have to check the options "Enable USB Controller" and "Enable USB 2.0 (EHCI) Controller" of the "USB" section (see http://www.ehow.com/how_7248690_sync-ipod_-itunes-virtualbox.html) of the virtual machine settings. It told me that you have to install extension pack to enable the EHCI option.
After I downloaded this extension (file name: Oracle_VM_VirtualBox_Extension_Pack-4.2.18-88780.vbox-extpack) from Oracle website and install it via [File -> Preferences -> Extensions], it told me the versions of virtual machine is too old to match this extension.
So I downloaded the "All distributions" edition of virtualbox on Oracle website (file name: VirtualBox-4.2.18-88780-Linux_x86.run). Remove the old version (v4.1.x) and install this 4.2 verison (sudo ./VirtualBox-4.2.18-88780-Linux_x86.run). Then install in settings. Then enable EHCI of the Windows 7 virtual machine. Then start it and plug in the iPod. After a while at [Devices -> USB Devices] I got the item "Apple Inc. iPod [0001]", check it and my iPod appeared in iTunes.
To add "The Well-Tempered Clavier" of Bach to iPod, I install soundconverter and convert all flac files to aac files with it. Then I import these aas files into iTunes and transfer them to my iPod.
So this is the whole story of using iPod on Linux.