customizing Mac login screen

I found the following web site has hints on how to customize all kinds of things on my Mac:

# http://www.macyourself.com/2009/03/11/mac-login-window-tricks-part-4-change-default-background-image/
# DEFAULT - sudo defaults delete /Library/Preferences/com.apple.loginwindow DesktopPicture
sudo defaults write /Library/Preferences/com.apple.loginwindow DesktopPicture /Users/javaswinger/nepal.jpg

# http://www.macyourself.com/2009/03/06/mac-login-window-tricks-part-2-add-a-custom-welcome-message/
# DEFAULT - sudo defaults delete /Library/Preferences/com.apple.loginwindow LoginwindowText
sudo defaults write /Library/Preferences/com.apple.loginwindow LoginwindowText "Welcome to Dharma & MacBook world"

# http://www.macyourself.com/2009/03/05/mac-login-window-tricks-part-1-unleash-hidden-system-information/
# use any of the following:
# HostName, SystemVersion, SystemBuild, SerialNumber, IPAddress, DSStatus, Time
sudo defaults write /Library/Preferences/com.apple.loginwindow AdminHostInfo Time