How to lock the screen in GNOME

I’m sure that many of you are used with the <Win>+<L> key combination in
windows, to lock the screen. In Ubuntu (the distro I use), the
corespondent shortcut is <CTRL>+<ALT>+<L>. But, in many other distros
there is no shortcut for this command. Here is what you can do to assign a shortcut for locking the screen. (In order to do that, you have to activate the Win key. Read “How to use the Win key in Linux” to find out how to do it.)
Open the gconf-editor by typing “gconf-editor” in the terminal.

nongeek@mma:~$ gconf-editor

Go to: apps>metacity>keybinding_commands

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