Mouse for Trembling Hands
IBM is selling a mouse — the Assistive Mouse Adapter — specifically for those who cannot control the trembling in their hands. It filters out unintentional movements using algorithms similar to those used in image stabilization systems in camers. You can adjust it to accommodate the severity of the tremors and to filter multiple clicks. No software to load. Plugs in between computer and your mouse.
You can purchase it from Montrose Secam for $99.