OS X.5 / X.6 - automount extenal drives on boot:
Normally external drives are only mounted if a user has logged in and the Finder has started. To automount external drives, login as privileged user, open the Terminal and type
sudo defaults write /Library/Preferences/SystemConfiguration/autodiskmount AutomountDisksWithoutUserLogin -bool YES
This corresponding .plist-file doesnt exist, so it will be created.