Resolution change manually on Ubuntu 10.04

1. Show current setting
   $ xrandr -q
   Screen 0: minimum 320 x 200, current 1024 x 768, maximum 8192 x 8192
   VGA1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 338mm x 270mm
   1024x768 60.0*
   800x600 60.3 56.2
   848x480 60.0
   640x480 59.9
   
2. Get new mode line with new resolution
   $ cvt 1280 1024 60
   # 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
   
3. Create a new mode for new resolution
   $ sudo xrandr --newmode "1280x1024_60.00" 109.00 1280 1368 1496 1712 1024 1027 1034 1063 -hsync +vsync
   
4. Add the new mode
   $ sudo xrandr --addmode VGA1 "1280x1024_60.00"
   
5. Check if new mode exist?
   $ xrandr -q
   Screen 0: minimum 320 x 200, current 1024 x 768, maximum 8192 x 8192
   VGA1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 338mm x 270mm
   1024x768 60.0*
   800x600 60.3 56.2
   848x480 60.0
   640x480 59.9
   1280x1024_60.00 59.9
   
6. Use the new mode
   $ sudo xrandr --output VGA1 --mode "1280x1024_60.00"
   

And you might get your new resolution you desired.