The system is called the Tongue Drive, and it relies on a waterproof retainer on the roof of the mouth containing a Li-ion battery, induction coil for charging, and and several magnetic contact points to detect the position of the tongue-mounted magnet. It'll then beam the signal wirelessly to a mobile device--iOS devices like the iPhone and iPod Touch are mentioned--and the mobile device shoots those commands over to whichever device is meant to be controlled. Theoretically you could use the Tongue Drive for just about anything, but the engineers are specifically looking to replace what's called the "sip-n-puff" system for controlling wheelchairs, sort of like blowing into a straw. The Tongue Drive part of a new crop of wheelchair controls that are far more customizable than before. It's a pretty interesting field--read more about them here.