cheat sheets.

See:
http://promberger.info/linux/2007/12/20/external-monitor-on-thinkpad-x41-running-
ubuntu-gutsy/
See:
http://www.thinkwiki.org/wiki/Installing_Ubuntu_6.06.1_on_a_ThinkPad_R60e#Intel_9
5GM_with_the_xorg_Intel_driver

Project to external monitor:
  xrandr --output VGA --auto

Project to external monitor with a specific resolution:
  xrandr --output VGA --mode 1280x1024

Turn off projecting to external monitor:
  xrandr --output LVDS --auto --output VGA --off

One big virtual screen across both monitors:
  xrandr --output VGA --right-of LVDS --mode 1280x1024