"If you saw an EMC Balun hanging off your keyboard's wire you'd hardly be surprised. Who could blame you? What's so surprising about a mere EMC Balun? It wouldn't even warrant a second glance. What if i was to tell you that this particular EMC Balun was actually a Keyghost? You'd probably start to get a bit worried. If I told you that the Keyghost could log up to 200,000,000 keystrokes with 128bit encryption in its Pro flavor and up to 97,000 keystrokes with no encryption in its Standard flavor you would have good reason to be worried."
FULL STORY @ ACIDHARDWARE (http://www.acidhardware.com/reviews/keyghost/keyghost.shtml)