Disable - Enable Touchpad is a very very simple servicemenu to disable or enable your touchpad (e.g. if sometimes you use a USB mouse, the touchpad may become annoying).
Notice: it only works if it is a *synaptic* touchpad
There are plenty of ways to disable your touchpad, for example through the comamnds synclient TouchpadOff=1 or synclient TouchpadOff=0 which is exactly what this servicemenu does.
At reboot, this setting is reset and touchpad is enabled by default. If you want to disable it permanently, you can comment the touchpad section in /etc/X11/xorg.conf
1) copy the file Disable_Enable_Touchpad.desktop in the KDE servicemenus folder, that is located in /home/your_username/.kde/share/apps/konqueror/servicemenus
2) just leave the file Disable_Enable_Touchpad.desktop in same folder and right click it; on "action" you'll find the touchpad entry