Aside from the Windows Power Management
scheme and your OEM power management system,
(which should already eek out every minute
of battery juice) and assuming you have already
properly setup the options ie. dim down lcd; step
down CPU; spin down drives and power off ports
etc etc... there is really is no other add on
software that can preserve battery life further.
You can however shut down non essential services
via admin tools and turn off all radios (wifi/
bluetooth) for a list of services to shut down
try googling for them. Just another thought came
to my mind was CPUIdle... havent tried it but it
cools your cpu but lowering the cycles when idle
this would also preserve battery life too (at the
expense of power and speed of course) worth a
try i suppose...