About Apple Mini DisplayPort to VGA Adapter MB572Z/B by Apple:
The new MacBook, MacBook Pro, and MacBook Air each have a Mini DisplayPort that allows you to connect an external display or projector using an adapter. You can use an external display as your main workspace or to extend your desktop, or you can work in mirrored mode with a projector so you can view what your audience sees. Use the Mini DisplayPort to VGA Adapter to connect your MacBook, MacBook Pro, or MacBook Air to a standard analog monitor, projector, or LCD that uses a VGA connector or cable. Review the documentation or check with the manufacturer of your monitor to make sure you re choosing the right adapter.