NetStumbler is a tool for Windows that facilitates detection of Wireless LANs
About
NetStumbler (also known as Network Stumbler) is a tool for Windows that facilitates detection of Wireless LANs using the 802.11b, 802.11a and 802.11g WLAN standards. It runs on Microsoft Windows 98 and above. A trimmed-down version called MiniStumbler is available for Windows CE.
NetStumbler is commonly used for:
* Wardriving
* Verifying network configurations
* Finding locations with poor coverage in one’s WLAN
* Detecting causes of wireless interference
* Detecting unauthorized (â€Ârogueâ€Â) access points
* Aiming directional antennas for long-haul WLAN links
http://www.netstumbler.com/