Even if your desktop has a display adjustment GUI, it may not support all of the features that you want/need to adjust, or you may simply find it more powerful to use the xrandr utility, one of many handy such tools in the xorg-x11-server-utils package. Some GUI front-ends are also available, like 'krandrtray'. With the xrandr command, you can query and change available screen resolution and refresh rates "on-the-fly":

	$ xrandr -q
	Screen 0: minimum 320 x 200, current 1024 x 768, maximum 2048 x 2048
	VGA1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 300mm x 230mm
	   1024x768       85.0*+   75.1  
	   800x600        75.0  
	   640x480        75.0     60.0  
	   720x400        70.1  
	   1280x1024_60   60.0  

Note that the current setting is marked with an asterisk. You can change the screen resolution and refresh rates with, for example:

	$ xrandr -s 1024x768 -r 68.0

Changes are applied immediately when you press . Read: 'man xrandr' for complete details.

Increase Resolution

If you want to add a mode with resolution 1280x1024, you can enter the following command:

	$ cvt 1280 1024
	# 1280x1024 59.89 Hz (CVT 1.31M4) hsync: 63.67 kHz; pclk: 109.00 MHz
	Modeline "1280x1024_60.00"  109.00  1280 1368 1496 1712  1024 1027 1034 1063 -hsync +vsync

Now you need to create a modeline

	$ xrandr --newmode "1280x1024_60.00"  109.00  1280 1368 1496 1712  1024 1027 1034 1063 -hsync +vsync

Now you need to add the above mode using the following command

	$ xrandr --addmode VGA1 1280x1024_60

Here for VGA1 you have to use what ever that was there for $ xrandr output

	$ xrandr --output VGA1 --mode 1280x1024_60

Running these would change your resolution but this is temporary.these steps were done to make sure that these commands work

Now we need to make these changes permanent

Now you need to edit the default file

	$sudo vi /etc/gdm/Init/Default

Look for the following lines

    PATH=/usr/bin:$PATH
    OLD_IFS=$IFS

and Add the the following lines below them

    xrandr --newmode "1280x1024_60.00"  109.00  1280 1368 1496 1712  1024 1027 1034 1063 -hsync +vsync
    xrandr --addmode VGA1 1280x1024_60
    xrandr --output VGA1 --mode 1280x1024_60

Save and exit.

Reference:
http://forums.fedoraforum.org
http://ubuntuforums.org