laptop/second monitor/XFree86 - how to get X?

["Gary E. Bickford" <garyb fxt com>]

Folks,
My laptop screen got busted yesterday - I've plugged a monitor in the back,
and everything works fine except X.  When X starts, it goes to the LCD
screen.  Is there a quick/easy config fix for this?  I'd like to have X on
the 2nd monitor (although it'll probably only work at 640x480)  The laptop
is a Dell Latitude CPi if that makes any difference.