inSSIDer is a wireless network scanner for Windows, OS X, and Android. It was designed to overcome limitations of NetStumbler, namely not working well on 64-bit Windows and Windows Vista. inSSIDer can find open wireless access points, track signal strength over time, and save logs with GPS records.
For downloads and more information,
visit the inSSIDer homepage.
Used as a demonstration in a wireless security class. Very user friendly even for beginners. Easy installation with next to zero configuration required. Lists networks, encryption protocol used (WEP, WPA, etc), network type (ad-hoc, infrastructure) and a line graph for each network. A recommended download.