War-driving

Wardriving is the act of searching for Wi-Fi wireless networks by a person in a moving vehicle, using a portable computer, smartphone or personal digital assistant (PDA).

Software for wardriving is freely available on the Internet, notably NetStumbler, InSSIDer, Vistumbler, or Ekahau Heat Mapper for Windows; Kismet or SWScanner for Linux, BSDs, and Solaris; and KisMac for Macintosh. There are some for both Windows and Macintosh, for example, NetSpot There are also homebrew wardriving applications for handheld game consoles that support Wi-Fi, such as sniff jazzbox/wardive for the Nintendo DS/Android, Road Dog for the Sony PSP, WiFi-Where for the iPhone, G-MoN, Wardrive, Wigle Wifi for Android, and WlanPollution for Symbian NokiaS60 devices. There also exists a mode within Metal Gear Solid: Portable Ops for the Sony PSP (wherein the player is able to find new comrades by searching for wireless access points) which can be used to wardrive. Treasure World for the DS is a commercial game in which gameplay wholly revolves around wardriving.

War driving originated from wardialing, a method popularized by a character played by Matthew Broderick in the film WarGames, and named after that film. War dialing consists of dialing every phone number in a specific sequence in search of modems.

...
Wikipedia