If anyone is looking for a cheap, very functional, on-screen keyboard, go to www.IMGpresents.com they have a great on-screen keyboard that has also macro functionality. It costs about $25 and in my experience, is much better than any other software out there. I use whats called a headmaster, Prentke Romich Co. right now, it retails for about $995 I have also try the tracker system, but it was much less accurate than a headmaster. You can download a demo version of the software from www.INGpresents.com hope this helps.
Also, I use a trackman live cordless tracball. I can't write / type the mouse is functional. Buy it on ebay! much cheaper......