Is there some argument I can put in the grub boot command line in
/boot/grub/menu.list to cause X11 to re-evaluate the monitor or force a
particular resolution/frequency for the graphic login screen in ubuntu 6.06?

I have a machine that dual boots XP and ubuntu 6.06 which ran just fine
using a CRT.  I was given a Viewsonic vg800b 19" LCD (native 1280x1024) for
it today.   When I boot into ubuntu the LCD goes black with a small "Out of
Range" message in the middle of the screen after the startup messages but
before the login screen.  There is no problem if I boot Xp or even booting
to a Knoppix live CD.  If I put the CRT back on I see the gnome desktop was
set for 1280x1024 @ 75 Hz whereas the LCD monitor native is 1280 x 1024 @ 60
Hz for both real users.  I can change the resolution for them, but it does
no good since I can't log in with the LCD monitor attached.

Hopefully I should be able to boot to recovery mode or boot Knoppix and edit
/boot/grub/menu.list or some X11 configuration file in the ubuntu file
system to fix it.

-- 
Be who you are and say what you feel, because those who mind don't matter
and those who matter don't mind.  - Dr. Seuss