Have you taken it to the apple store? I think that would be the first step, as this seems to be a defective hardware issue.
I have a MacBook Pro, aluminum running Snow Leopard, 10.6.2.
When I type something, there are times when my cursor will spontaneously skip to another location. As an example: if I am typing this, the cursor might jump to the subject title area.I have been very careful to not touch the trackpad and still have this trouble. I posted this problem some time ago, but had no help or information about this at all. It is getting quite frustrating and I am hoping that someone out there will have a clue about this and perhaps a solution.
Would greatly appreciate any help with this.