NetStumbler

NetStumbler is a tool for Windows that allows you to Detect Wireless Local Area Networks (WLANs) using 802.11b, 802.11a and 802.11g. It has many uses: Verify that your network is set up the way you intendedFind Locations with poor coverage in your WLANDetect other networks that may be causing Interference on your networkDetect unauthorized Rogue access points in your WorkPlaceHelp aim directional antennas for long-haul WLAN linksUse it recreationally for WarDriving