While wireless networks are growing in popularity, monitoring these networks for abuse and intrusions is almost nonexistent. Although some intrusion prevention systems have recently appeared on the market, their intrusion detection capabilities are limited. Real intrusion detection in wireless networks is not a simple add on. This paper discusses the fundamental difference between wireless intrusion detection and traditional network intrusion detection and identifies some of the challenges that will need to be solved in designing and deploying a cost-effective wireless intrusion detection system.