How can I restart an iPhone 4S with a broken lock button and frozen springboard? My springboard has frozen and the lock button is broken (two months out of warranty and it's not classed as a hardware failure). 

How do I restart the phone given that I can't access any apps or settings?

Waiting for the battery to drain will take days, so that's not an option. Is there a way through iTunes to force a reboot or is there a program I can download to force a reboot?
Go to settings general then accessibility. Turn bold text on and it will reboot your iPhone and fix a springboard crash. I was having the same problem and lucked out and found this!