U.S. Tech Blog ...

i found it very annoying to use a touchpad in Ubuntu specially when typing...To add to the trouble my laptop does not have a manual turnoff switch for touchpads.....i came across the following post which describes how to disable Synaptic touchpad with a GUI interface..

If you are too lazy to remember and run 'gpointing-device-settings' in terminal , add command into the Applications submenu by --> (right click) Applications --> Edit Menus --> New Item


Update :------------------------------------------------------------------------------------ although at first 'gpointing-device-settings' looked great , it had certain limitations(ie:- timeouts can't be set,configuration issues)..therefore i had to go for a more crude method..
use 'xinput' to find device id for your touch pad..
$xinput list
mine was 13 (ie:-AlpsPS/2 ALPS GlidePoint id=13 [slave pointer (2)). I used this id to disable touchpad using
$xinput set-prop 13 --type=int --format=8 "Device Enabled" 0

Use System --> Preferences --> Startup Applications to add a startup script if you want to disable your touchpad from start :)