VAS

Mobile biggies are quaking at the idea of competition from a free, ad-based service

Imagine your cellphone as a mini marketing machine. As you head into your car after dinner, a text alert pops onto the screen of your handset announcing the 9 p.m. lineup at a nearby cineplex. You choose the Jodi Foster flick The Brave One and a promo video for the next Warner Bros. (TWX ) release, a George Clooney movie, starts running. Afterward, more text appears, prompting you to launch the phone's Web browser so that you can click through to buy the movie's ringtones and wallpaper.