Ubuntu Video - Ways to Change Resolution
Desktop Training - Ubuntu

Ubuntu 9.04 makes new improvements in screen resolution, enhancements and features but what good are they if you can't see your screen properly. The screen resolution is always a concern while setting up a new operating system. The resolution setup may vary for different graphics cards and their drivers. Upon opening the Ubuntu  desktop select the Gnome main menu by clicking on System --- Preferences --- Display.

Here you can see the configuration for a laptop.  The current resolution is 1280x800.  Note the refresh rate should not be increased beyond what your monitor can bear as it will burn it out, so read the manufactures info for your monitor.

screen resolution

Each user is allowed to have a separate resolution that fits their individual needs so no root password is needed to change this or for other items in the "Preferences" menu. Selecting Display from the menu brings you to the Display Preferences window. Here you can manually adjust the resolution, refresh rate rotation, or select the detect displays button to have Ubuntu automatically detect your display settings.

Now that you can change the resolution by using the desktop interface lets take a look at a quick command to change the resolution from the command line. On the Ubuntu  desktop panel select the Applications option. Next click on Accessories and open the Terminal option.

After you've brought up the terminal window you can easily change the resolution by typing:

xrandr -s 1024x768

Note ...only use that resolution if it fits your monitor.

Here are some additional options.

xrandr -s 640x480
xrandr -s 800x600
xrandr -s 1024x68
xrandr -s 1280x720
xrandr -s 1280x800

Whatever resolution you want to adjust the desktop to what your monitor can handle. . After you're finished press enter and the Ubuntu desktop resolution will be adjusted.