Reset your lost Mac OS X password
You can reset a lost Administrator (the original account you created) password in Mac OS X by utilizing a Mac OS X installation DVD, here’s how:
* Insert the Mac OS X DVD into your Mac’s DVD drive
* Restart the Mac and hold down the ‘C’ key to boot from the DVD
* You’ll see a language selection screen, select your language (English) and continue
* Navigate to the ‘Utilities’ menu, select “Reset Password”
* Select the Mac OS X boot drive
* Select the original user account (not the root user!) and choose a new password
* Reboot as usual
* Your Mac administrator password is now reset!
If you do not have an installer CD or DVD handy, you can also reset a forgot Mac password using a crafty technique.
[ screenshot from Apple ]