ok, so u don't hafta play around with it next time, u hafta make sure u have no CD in the stereo (in the front) and then simply press disc while the kiddies are watching the movie, the sound should then go through the speakers instead of the headphones.
also, if it's factory installed, there should be an A/V plug somewhere in teh back. since i've never sat in a 98-03 with the factory installed entertainment system, i can't tell u exactly where it is, but in my aunt's 04, it's in the very back seat, on teh left, in the wall.