inSSIDer from MetaGeek is a free Wi-Fi network scanner for Windows Vista and Windows XP. Because NetStumbler doesn't work well with Vista and 64-bit XP, we built an open-source Wi-Fi network scanner designed for the current generation of Windows operating systems. Inspect your Wi-Fi and surrounding networks. You can: Scan and filter hundreds of nearby access points. Troubleshoot competing access points and clogged Wi-Fi channels. Highlight access points for areas with high Wi-Fi concentration. Track the strength of received signals in dBm over time. Sort results by MAC Address, SSID, Channel, RSSI, Export Wi-Fi and GPS data to a KML file in Google Earth. Compatible with most GPS devices (NMEA v2.3 +).
What's new in this version: Version 188.8.131.523 update includes improvements, bug fixes, and a new look.