IBM developed a sniffing network much like AirDefense's: The platform is targeted at companies that will deploy the IBM sniffing devices around a building. The sensors look for rogue APs, denial-of-service attacks and compromised WEP keys.
IBM is a bit late to the game here. This article points out that AirDefense goes one step further than the IBM solution and can actually shut down APs. Also, the WLAN switch vendors that are targeting enterprises usually include rogue detection in their APs so customers don't have to deploy a separate network to detect trouble.