Cymouse - six degree-of-freedom positional and angular head tracking device 

Imagine being able to send and receive E-mail, browse the web, even turn on
the T.V. set using simple head movements. Cutting edge IR technology provides
silky-smooth cursor movement. Sensitivity is adjustable so each individual
can adjust cursor control to suit their needs. Cymouse is one of the
smallest, lightest, most comfortable head mounted control devices on the
market. The device is easily mounted on a desktop of laptop computer. Cymouse
performs all the functions of a standard keyboard or mouse. Clicking and
double-clicking are easy. Although Cymouse replaces trackballs, joysticks,
mice, and keyboards, it will still work with any other peripheral at the same
time. So if your special needs include use of a footswitch in conjunction
with the Cymouse head mounted control....no problem! 

http://maui-innovative.com/AssistiveTech.html