Newbury Networks announced WiFi Watchdog
Watchdog is an application will alert IT managers when an intruder is accessing a company's 802.11b network and will prevent the intruder from doing so. The software also pinpoints where an intruder is within 5 feet and allows IT managers to more effectively direct which parts of a network's coverage is active. How? I don't know but that's probably the secret you get after paying the $20,000. Read more here.