Firmware update for iPod Touch (iPhone)?

While some older versions of iTunes can currently be made to work with Wine (or Crossover), they cannot be used to update or sync newer iPods

The reason is that Wine lacks a handler for Windows USB device drivers, and the iPod acts as a custom USB device. This is the same reason that software that requires a special key dongle also doesn't (yet) work in Wine. There are some preliminary patches available for this, and you can read more history on the Wine wiki, however don't expect anything to work.

The only iPods that currently work in Wine are really old iPods that act as simple USB mass storage devices. And even then you still need to find an older, working iTunes.

Because of this problem in Wine, to do the firmware upgrade you'll need to either setup a virtual machine with Virtualbox or VMware or, perhaps more simply, borrow someone else's computer.

I don't know if this works with your iPod touch, but it works for my older iPods: http://code.google.com/p/ipod-update/

Looking at the Crossover page for iTunes, a couple of versions have been reported to work somewhat. Crossover costs money, but it may be worth it for you.