Thumbscript  
   Offers hard- and software solutions for entering text using a thumb-operated 9-keys keyboard.
   http://www.thumbscript.com

Handykey Corporation  
   Sells combination of chording keyboard and mouse, called Twiddler, that weighs 4 ounces and fits in the palm of a hand.
   http://www.handykey.com/

L3 Systems  
   Manufacturer of a 39-keys wrist-worn PC keyboard as well as customized keyboard controllers.
   http://l3sys.eskimo.net/

WetPC  
   Makes an intuitive human machine interface suitable for wearable, handheld, underwater and mobile computing.
   http://wetpc.com.au/

Matias Half Keyboard  
   One-handed keyboard for PDAs and PCs. Special version with straps available. Use is explained in a flash demo and a downloadable one.
   http://halfkeyboard.com

NumberPad as one-handed Keyboard  
   The linux kernel patch (2.2 & 2.4) allows to type two-digit numbers on a number pad to simulate characters and special keys.
   http://www.fourtytwo.de/

FrogPad  
   One-handed 3x5 USB keyboard with "patented" key layout but no straps. On-line available are a shop, training material and licensing ideas for different devices.
   http://www.frogpad.com

Inference Group - Dasher Project  
   A software solution for entering text by zooming through letters. A graphical demo, versions for different systems and languages and ideas for appropriate input hardware are provided.
   http://www.inference.phy.cam.ac.uk/dasher/

Lightglove  
   Air typing by blocking watch-like attached lasers with fingers. Presents some infos on technology, photos and the patent abstract.
   http://www.lightglove.com/

Kitty  
   Typing by touching the thumbs with different fingers and at different positions analog to a normal keyboard. With Flash demo, prototype photos and press overview.
   http://www.kittytech.com/