there's away to force reset it while its connected to your computer, although I forget exactly howAnyone like to jog my memory?
only way is a forced recovery mode
huck ipod up to pc and load itunes up............... hold the home and lock buttons, touch will turn off keep the buttons held down when the apple logo appears let go of the lock key only leaving home button down eventually the itunes logo and a usb connecter will show on screen and itunes will detect the touch in recovery mode. click ok then hold shift and click restore now its a case of pointing to where the 1.1.1 restore file is. (this is normally at %appdata%\Apple Computer\iTunes\iPod Software Updates on a pc)
Oh that stinks! The only way to get out of recovery mode is to restore. Sorry dude.
U can always try restoring it usin iTunes but if u like ur jailbreak don't upgrade to 1.1.2 since most jailbreaking programs dont work for that iPod version yet, such as jailbreakme.com... or try restarting ur iPod like andy said.