NetStumbler [1] is a free packet sniffer utility used to locate Wi-Fi networks. It's one of the first tools of its kind and arguably still the best. So much so that it is the standard product used by war-drivers in their perpetual search for free bandwidth via unsecured Wi-Fi networks as well as road-warriors looking to connect their laptops back to the office.

Basically it's a wireless packet sniffer that lists all networks available at a given geographical location. For each network it displays over 20 different parameters including the signal strength, noise level, encryption method used, GPS coordinates and more.

It's a great product with a couple of caveats: first, it only works with specific wireless card chipsets and if yours is not one these then you are out of luck. However, most Centrino-based laptops work fine including many Dells and IBMs. Second, the program won't connect you to a network; you have to do that by other means.

That said, NetStumbler is a valuable product for any laptop user who accesses Wi-Fi systems while on the road. It's also a standard tool in trade for IT security workers who need to audit Wi-Fi security.

[1] NetStumbler
Website: http://www.netstumbler.com/about/
Download link: http://www.netstumbler.com/downloads/
Author: NetStumbler.com
Current Version: 0.4.0
Version Date: April 21, 2004
Download File size: 1.3MB
License: Beggarware
Operating Systems supported: Windows 2000/XP
Additional Software Required: You may ned to update your wireless card firmware and/or drivers
64 Bit capable: No
Portable version available: No
Non-English languages supported: No
Other relevant information: None