Since you use intel driver it is always opensource and will work with xrandr.
Just verify if it is the case:
grep "physical size" /var/log/Xorg.0.log
if you see any mention of VESA you need a better intel driver, say ubuntu livecd has one.
if it is driver named "intel" or "INTEL" you should use xrandr, or in KDE you must install krandrtray (if it is not present by default) (i.e Alt-F2, in the box on top type krand.... and it should fill with krandrtray - resolution changer.
Unless you change xorg.conf your X11 will come up in "default resolution" on "default monitor" and krandrtray will set good display after login. If you feel unhappy about this just drop a line, i will write guide on how to convert xrandr display into xorg.conf
Graphiccard would be nice to know, and if you're talking about a a Live-CD. – Bobby – 2010-03-10T16:36:15.150
Intel GMA something, I think. – None – 2010-03-10T16:42:38.660