Your Mac desktop or laptop's screen is just as delicate as the Mac trackpad. To clean it, you should use a soft, lint-free cloth that is just slightly damp with water. Apple warns against using glass cleaners like Windex or other products that contain alcohol. It's best to just use a clean cloth with a small amount of water. Be very careful because if excess moisture from your cloth gets into the microphone, camera, or other crevices, you could ruin them, or the computer.
If your screen isn't coming clean enough with just water, you can try a screen cleaner specifically designed to clean Mac screens -- Monster iClean. It's available at the Apple Store and is the only cleaner and cloth designed to be safe for Mac screens.
For more information on Mac products, see the links on the next page.