phreaking, yea!
anyway... i had the same problem: as it turns out the XFree86 organization
has temporarily phased out XF86Config with XFree86 4.0 (the x server included
in debian's testing distribution).
They suggest using either xf86cfg or XFree86 -configure, but both of these
caused my machine (a dell dimension) to crash as (i think) they are
essentially the same program. Try downloading the xserver-xfree86 package
and running one of those. I'd be interested to know if it works on your
machine or not.
I eventually wound up running xf86config to get a basic configuration file
and then making a few minor changes by hand.
