An interesting software replacement for keyboards. I tried the software and
while I am not yet convinced (after a few minutes of using it) that it is
fast for desktop PCs I can easily see that it makes sense on PDAs or Tablet
PCs. Unfortunately the source has not yet been released and it probably is
not written in Smalltalk.

"Dasher is an information-efficient text-entry interface, driven by natural
continuous pointing gestures. Dasher is a competitive text-entry system
wherever a full-size keyboard cannot be used"

Dasher
http://www.inference.phy.cam.ac.uk/dasher/

Dasher Demo
http://www.inference.phy.cam.ac.uk/dasher/DasherSummary2.html

Movies of Dasher in use
Dasher running on an Handheld
http://www.inference.phy.cam.ac.uk/djw30/dasher/movies.html

Andreas