First, simply slip the wire at the top of the threader through the needle's eye. This is easy to do, since the wire is stiff and doesn't easily bend. Next, just run the thread through the exposed wires. You can bend the wires into a loop to make the metal hole even easier to fit the thread through. Then, grasp the needle in one hand and pull the threader out with the other. Presto! Your needle is threaded and ready to use.
(From the Groovy Gadgets shelf.)