Finally today we've uploaded the new Xrandr GUI to Ubuntu Hardy. I mentioned working on a tool a couple weeks ago; I discovered that Soren Sandmann was also working on such a tool and was further along, so I shifted focus to getting that tool ready for integration in Ubuntu.
The above photo shows two laptops, one connected to an external monitor, the other to a projector; resolutions, rotations, and so on can all be handled on a per-monitor basis. The projector image is hard to see since it's so bright, but it's working fine with these laptops.
This tool also has a Cairo-based graphical layout to show the screens; notice how it detects and displays the monitor's name.
You'll notice the 'clone screens' checkbox; currently the utility does not have a way to specify left-of/right-of, so it just does cloning for now. It's entirely within the design scope of this tool to do that, so expect to see that capability in coming months. (For now, I'm going to leave the clone checkbox out).
The tool allows rotation as well.
One issue I found is that it only allows making changes to one screen at a time. If you need to change the other monitor's settings, I find it works to disable the first one (set resolution to 'off'), make the changes to the second, and then re-enable the first.
CAUTION: Xrandr is buggy on certain hardware. It's not this GUI tool's fault (you can usually replicate the bugs using the 'xrandr' command-line tool), but the GUI increases the exposure to these bugs since it's so easy to play with them now. For instance, some hardware locks up or performs badly when rotated. Others exhibit lockups or corruption when scaling up or scaling down. So, if you want to experiment, please be sure to save your work first. ;-) Bugs should be reported against your video driver, not against xrandr or this gui.
to Brian P Wunderlich: GUI mean interface