Finally, LCD display pivoting for Mac OS X: Jim suggested a trick to access to "Rotate" option in the Display System Preferences panel, but I notice that in Mac OS X 10.4 Tiger, no trick is necessary: "Rotate" just shows up in the preferences panel on my rotatable LCD display! (Maybe this is new with Tiger? I couldn't find any info of this sort back when I was looking.)

It's not automatic: it won't just detect that you twisted your screen and adjust, you have to go to the preferences panel. But who needs that? I'm writing this on a gorgeous tall screen. I probably wouldn't do this all the time, as horizontal space is actually more useful most of the time. But it's nice to know I have the option.