Take that, OnStar.

Mazda joins a growing number of automakers capitalizing on the popularity of the iPhone to offer apps that cover everything from free to navigation to remote unlock to roadside assistance. It's the latest entry in a roster of applications. Mercedes will let you lock or unlock your car from an iPhone. Smart will soon let you play Internet radio stations and get turn-by-turn directions from an iPhone app. Now Mazda is introducing an app for roadside assistance.

Should the unforeseen occur--a flat tire, dead battery, or accident--the owner can can use the free app to contact the closest service provider by tapping on the application's icon. While you're waiting for the tow truck, the app will periodically give you an ETA as to when help will arrive (that way you can go back to Twittering). The primary benefit of the free Mazda application is that it will find your location automatically. In other words, a tow truck can find you without having to rely on vague instructions like, "I just passed exit 15 on I 95."

Unlike the e911 service in Ford's Sync or GM's OnStar, calls are not made automatically when, say, a car's airbags are deployed. It cannot be operated via voice commands, either, should you be in real trouble. And the application lacks other features of say, Smart's forthcoming application. There's no turn-by-turn navigation, for example, or Bluetooth Internet radio function. Blackberry owners and Android phone users are also out of luck: the Mazda application only works with the iPhone 3G and iPhone 3GS.