12v power from map light

There isn't a whole lot of activity on this forum, but I'll ask my question anyway.

I'm looking to get 12 volts out of the map light area up at the top of windshield. I want to wire up a charger for my cell phone so I don't have to run a wire up from the cigarette lighter.

Any tips? tricks? suggestions? funny stories? ... Anything?

BUMP
Anyone have :2cents:

Yes, find the constant +12V line and tie into it, and provide a good ground also.