Setting up dual displays in Ubuntu (VGA & DVI)

For a time, I've been wondering how to set up dual displays in Ubuntu. I have two screens connected, one via DVI and one via VGA. Whenever I tried using both, the VGA screen would always be placed to the left, whatever setup I made in the display settings. Finally, I found the solution in Mark's blog post.

The key is the xrandr command line function. I first enabled both displays under the display settings, and then used the command

xrandr --output VGA1 --right-of DVI1

Note that you may have to call the xrandr function without any arguments first, to find the name for each screen.