Fedora Linux with Multiple Monitors

Quite annoyingly, a default install of Fedora with XFCE on a laptop computer doesn't support multiple monitors properly.  If you plug an external screen in, the only option is to mirror the main screen (using the function keys, fn-F3 or some such), which is seldom what I want.  I prefer having a bigger desktop stretched over both screens.  Even though the two may not have the same resolution, I think that it is a better use of pixels.

Old Fashioned Setup

Sometimes the prehistorical command line works best.  The two screens can be configured with xrandr, but one has to remember to rerun xrandr before the external screen is unplugged, to exclude it (turn it off).  It can be made more convenient by hooking two scripts to a pair of hot keys, which would bring your laptop machine back into this century.

First you need to do some sleuthing.  Simply run xrandr with no parameters:

$ xrandr

Screen 0: minimum 320 x 200, current 1366 x 1536, maximum 8192 x 8192

VGA-0 connected 1024x768+0+768 (normal left inverted right x axis y axis) 304mm x 228mm

   1024x768       74.9*    75.1     70.1     71.8     60.0  

   832x624        74.6  

   640x480        72.8     75.0     66.7     60.0  

   640x400        70.1  

LVDS-0 connected 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm

   1366x768       60.0*+

   1152x768       59.8  

   1024x768       59.9  

   720x480        59.7  

   640x480        59.4

From this command, you can see that the displays are named LVDS-0 (laptop) at 1366x768 and VGA-0 (monitor) at 1024.768. 

Configure the monitor VGA-0, to the right of the laptop screen LVDS-0:

$ xrandr --output VGA-0 --auto --right-of LVDS-0

To disable the external screen before unplugging it:

$ xrandr --output LVDS-0

Graphical Setup

Alternatively, use the graphical utility arandr:
# yum install arandr

Run that utility and click-drag-drop the screens where you want them!

Obstreperous Hardware

Sometimes you encounter weird hardware that hangs the system when X.org tries to probe it.  In these cases you need to create an Xorg.conf file and configure things manually.  See this link
http://fedoraproject.org/wiki/How_to_create_xorg.conf

'Hope that helps!