Yes. your ipod is a 60-30gb portable disk. just enable disk mode in the prefs. but be warned. Since the move to usb, the spinning hard disk uses more power than what USB can supply, during that time, the ipod will run off the battery. thus draining the battery instead of charging it. Also, is will cause the ipod's battery to go through more charge cycles, thus wearing your battery significantly more. One of my ipods had a really short battery life, despite moderate/low usage, and it was due to heavy disk usage (I picked the 40gb for a reason, and regularly transfered multiple GB of data.) Upon getting my other ipod, I've only used firewire to transfer files, so my battery is no longer affected. But I learned the hard way.
So if your intention is to use it as a pocket HD, just be aware of what USB can do to your ipod.