Tested: T-Mobile GSM phones CAN unlock your car.

wsdmag.com — I was skeptical, to say the least, about this rumor, and was about to dismiss it as one more Internet hoax. But I thought I better try it out first. Well, low and behold, it works. I tried it with a Motorola v330 GSM cell phone, and it reliably opens (and relocks) the car.