you can remove the drive from your PowerBook and then try connecting it as an external drive to another Mac. either install the drive mechanism into an external USB2.0 or FireWire enclosure, or use something like this [http://www.newertech.com/products/usb2_adaptv2.php|USB Universal Drive adapter]
of course if your hard drive is actually dead, this won't help, you may need more extreme measures (like a data recovery $ervice) to recover your data...
but before doing that you should first check if it's something other than your hard drive that is preventing your PB from starting up.
Have you tried booting from your OS install disc? try to reboot your machine with OS disc inserted and holding down "C" key. if you can successfully boot, then try to run Disk Utility to verify and repair the disk.