THis is something that first showed up in 03 Matrix owners, and some vibers have had it as well. I believe the solution is to replace the headlight switch on the steering column, and a workaround is to push the turn signal lever into high beam mode when you turn the car off. The auto headlights will go off when you turn off the car, but being in high beam mode seems to prevent the hedlights from coming on by them selves. There are some threads here about this, somewhere. edit - one is
http://forums.genvibe.com/zerothread?id=2686 I know there are others.Welcome to genvibe