Starting this spring, OnStar will begin selling their OnStar Anywhere product for $299. Essentially it's an OnStar-equipped rearview mirror that you swap out for your existing mirror. It's designed to allow access to many of OnStar's services for either a monthly or annual fee. Because the mirror itself includes accelerometers, it will allegedly be able to detect a crash and call OnStar for you. In addition, it provides access to emergency services, stolen vehicle location (it has built-in GPS too), turn-by-turn navigation (call them, tell them where you want to go, and OnStar will download directions into your mirror), roadside assistance and hands-free calling via bluetooth to your phone.
Now I'm ambivalent about OnStar. Frankly I don't see the point, and I think their fear-mongering TV commercials are patronising and unethical. But this at least product does get rid of the biggest evil - because it's a standalone device, it's not hooked in to your car's on-board computer or engine management system, meaning it's not open for hacking and abuse. Of course this also means that if you're dumb enough to lock your keys in your car, GM can't unlock it for you.
However because it has a mic in it for the hands-free telephone integration, OnStar will be able to listen in to whatever is going on in the car, whenever they want, and the GPS can be used to track you without you knowing. Both have happened before, and both will happen again - don't kid yourself that the law will protect you on that front.
So if you're desperate for the mental crutch that OnStar provides, and don't mind a constant GM spy in your car, it's yours shortly for $299 and a recurring fee.