I have been struggling with a jittery touchpad on my netbook.
After some observation, I have noted that it is more jittery in the vertical plane than the horizontal movements.
Initially I gave some attempts to tweaking the mouse settings which yielded no good results. There was no default touchpad configuration panel in KDE Settings.
I installed kcm_touchpad and synaptik from repos and rebooted. This however produced the following error
synPS/2 Synaptics Touchpad; Synaptics Gestures; no such property
There were 2 entries under Lost and Found in KDE Settings, the first one just crashed whenever clicked on and second one gave a configuration screen where settings could be adjusted. They seemed to have some results but my tweaking produced some unwanted results and I reset everything to defaults.
In spite of that, sometimes I felt touchpad had become MARGINALLY better (purely subjective)
Recently I have installed Pardus 2011 on the same netbook. It ships with a touchpad configuration tool under KDE Settings > Hardware > Input devices > Touchpad.
It has one of the best touchpad behaviour I have seen in Linux distros. It is closes to how touchpad behaves under Windows.
I could not find a xorg.conf in that installation. I thought there might be something useful which if I copy to my PCLinuxOS it might solve this problem.
I am waiting for more light on this matter.