ok assuming the car is right outside your home, what about a blowdryer on a long extention cord?
(assuming no lighter is on hand for the hot key trick).

or even a pocket travel hair dryer?

I've never tried it but I think the difficulty would be getting the hot air into the lock. Simply heating up the outside of the lock is unlikely (IMO) to melt frozen water on the inside. I think the surface area of the car door would dissipate the heat too fast for it to penetrate. At best, it would probably only melt the ice long enough for you to unlock the door and then refreeze.

As I said, I've never tried it so maybe it would work. I usually just climb in the passenger door. <img src="images/graemlins/smile.gif" alt="" />

(For those who are wondering, I've never had both doors freeze shut on me, even in Calgary. But since I'm single/no kids, the passenger side door lock gets a lot less wear and tear than the driver side, which is probably a factor.)