Mouse anti-tremor solution?

My 73 year old mother is a surprisingly savvy computer user. She uses her computer for research almost daily. As she has gotten older, she has developed a tremor in both hands. This makes using the mouse difficult when clicking on small items on the screen. She currently uses Windows XP. Is there software or hardware that can dampen her tremor so she can continue to use enjoy her computer?

Have you tried SteadyMouse? It looks like it was designed for your needs. Hasn't been updated (from the looks of it) for a while- but if it does what you need who cares (runs on XP).

And then there's this crazy expensive solution, but I'd try the free software first.

Have you considered the accessibility options to Control the mouse pointer with the keyboard (Mouse Keys).

That should allow her to move around the screen with the mouse and then switch to the keyboard for more precise movement.

Here are the accessibility options in Windows XP.

If nothing else, reducing the mouse movement speed could make more accurate clicking easier

Edit: On a side note, my mother also has some slight hand tremors, although not that bad, but has an easier time using a Trackball instead of a mouse. Results may vary.