But, if you have iTunes on Windows somewhere (like in Fusion or that old HP notebook) you are still in luck.
Why would you jailbreak an iTouch/iPhone? Because Apple has a stranglehold on the applications that can be added to the devices, and has refused to allow alternatives to built-in apps like Safari, Mail or iTunes. Or, maybe you don't want/can't afford to pay AT&T's outrageous international roaming rates.
This is another slide in the descent of Apple becoming the old Microsoft - only worse, because they own the hardware too.