HERNDON, Virginia — Audi of America is using the iPhone to help launch its 2009 A4. On Thursday, it announced the release of what it calls 'the first ever iPhone application from an auto manufacturer.'The application is free on Apple's iPhone Application Store. It provides consumers with the Audi A4 Challenge, a driving game that uses the iPhone's accelerometer or motion sensor to steer a digital version of the A4 through a series of courses.Audi has also set up the A4 iPhone experience Web site for iPhone users. Goodies such as an exterior color customizer and a link to install the Audi A4 Challenge application can be found there.What this means to you: Audi brings mobile marketing to your iPhone — and it likely will not be alone in this effort. — Anita Lienert, Correspondent