The latest tool to emerge from the home brew community is a program called DS2Key (for Nintendo DS), which features a "Wardriving" app (using the DSWifi programming library by Stephen Stair) that displays the SSID, WEP status, MAC addresses, and signal strength for whatever WLANs happen to be broadcasting nearby. Auto-refresh means that while you're driving around, looking to help your neighbors beef up their network security (i.e. "it's not a virus, it's a proof-of-concept"), DS2Key automatically updates all pertinent info.