/. discussion of "What's killing your WiFi?"

http://mobile.slashdot.org/story/11/05/30/1733231/Whats-Killing-Your-Wi-...

http://www.kismetwireless.net/

Kismet is an 802.11 layer2 wireless network detector, sniffer, and intrusion detection system. Kismet will work with any wireless card which supports raw monitoring (rfmon) mode, and (with appropriate hardware) can sniff 802.11b, 802.11a, 802.11g, and 802.11n traffic. Kismet also supports plugins which allow sniffing other media such as DECT.