[braindoc]

Here is another method:

Using a registry editor go to "HKLM/System/GDI/Rotation".
Change "HideOrientationUI" from 1 to 0.
Change "LandscapeFixed" from 1 to 0.

This now gives you the option of choosing the 3 rotation options under "Screen" in system settings (Portrait, Landscape (right-handed), Landscape (left-handed)).

Now, under "Buttons" in the Personal settings you can map the media button to rotate the screen for you. This gives you the ability to rotate the screen whenever you want regardless of how you are holding the device. I find this much more useful than auto-rotation.