Hang on to the power button and home button until device shuts down, then let go of power button but NOT the home button. Then the ipod will go into restore mode, at which you can let go of the home button and alt-click restore and choose file 1.1.1.
and you're on your way back to re-JBing it.
(man... i've had to do this so many times i can do it without thinking anymore haha... learning from mistakes)