If you are a windows user and have only USB2 you still need a firewire card to charge your ipod.
From Apple's site:
USB 2.0 + FireWire Cable (for PC)
For Windows users, the Dock Connector to USB 2.0 + FireWire cable is available for syncing via USB 2.0* and charging via FireWire.
Why even go USB2 if firewire is still needed?
From Apple's site:
USB 2.0 + FireWire Cable (for PC)
For Windows users, the Dock Connector to USB 2.0 + FireWire cable is available for syncing via USB 2.0* and charging via FireWire.
Why even go USB2 if firewire is still needed?