Kismet is a 802.11b wireless network sniffer. It is capable of sniffing using almost any wireless card supported in Linux, which currently divide into cards handled by libpcap and the Linux-Wireless extentions (such as Cisco Aironet), and cards supported by the Wlan-NG project which use the Prism2 chipset (such as Linksys, Dlink, and Zoom). New is the the hostAP driver also works. This is the best driver for Linux i know.

Download mirror: Kismet

Screenshot of Kismet