A must for security-conscious users!
Setting the Open Firmware password with the OFP utility prevents unauthorized users from starting up the computer from a volume other than the one you have chosen as the startup disk. The password is required to boot from an external FireWire disk, a CD-ROM drive, or another partition or disk inside the computer.
NOTE: For 10.3.9 and earlier ONLY! 10.4 and later, copy the OFP tool from /Applications/Utilities/ on the install DVD.
Does NOT fully support the new EFI firmware of Intel Macs. Some have reported that a password can be set, but it cannot be changed or removed -- use caution!