Enable firmware password on osx: This post will show you how to enable the firmware password on osx
firmware passwords will protect your mac from:
booting from a cd or dvd
booting from the diagnostic utility on the install dvd
booting from the network
booting from a different target drive
booting in single user mode
starting in safe mode
to enable the firmware password you need to boot your mac from your install disc [hold ‘c’ during startup]
once the cd has booted select
utilities > firmware password utility
tick the box that says ‘require password to start this computer from another source’
enter your new firmware password
Would you know how to do this on Lion since there is no install disk?