Vistumbler is a newer open source stumbler first released in 2007 and updated as lately as 2010. It displays the basic AP details, including the exact authentication and encryption methods, and can even speak the SSID and RSSI of APs.
Similar to NetStumbler, you can view a list of all APs or drill down to those categorized by authentication, encryption, channel, network type, and SSID. You can also view graphs of the AP signals in addition to viewing text readouts. It’s highly customizable and offers flexible configuration options. For example, you can define and save AP names to better distinguish them in the future. In addition to basic GPS support to record AP locations, it supports live tracking within the application using Google Earth.
However unlike NetStumbler, Vistumbler only gives you the signal levels and doesn’t include the noise levels. Thus it doesn’t report the signal-noise-ratio (SNR) values, which is usually more helpful than just the plain signal levels.