Do you use a drawingtablet as mouse? Because a Wacom tablet can't handle radio interference, which you obviously have when using wireless lan. I have this problem too, even when i'm touching nothing, my mouse vibrates 1 pixel vertical or horizontal (this only happens sometimes, it depends how close my mouse is located to the edge of a pixel in the tablet, with some interference my mouse virtually moves across the edge to another pixel and then ofcourse it moves on my screen too, and back... complicated digital stuff
![:S](images/smilies/msn_confused.gif)
), when I turn off my wireless lan it's gone (stable and absolute position)... maybe this helps...
EDIT: By the way, when my mouse isn't bugging, it does work here...