The GNOME On-Screen Keyboard (GOK) is an accessibility interface
that gives you control of your system without needing a keyboard.
The GOK makes available a hierarchical button system that enables
keyboardless entry of common accelerators, and contains a
clickable keyboard that sports suggested autocompletion of many
common words, and even some commands. The GOK will provide an
alternative interface to common commands and functions within
applications that utilize the AT SPI.

The GOK is designed to be usable by many alternative input
methods, i.e. not a common keyboard and mouse combination.

WWW: http://www.gok.ca