Asset-tracking software firm Ekahau releases tool to discover, map signal strength of Wi-Fi networks: HeatMapper, a free Windows XP/Vista application, performs the neat trick of letting you walk around your office or home while it continuously scans for Wi-Fi networks. When you stop warwalking and inform the program of such, you're presented with a heatmap of every network found. This lets you survey interference and see how your network deployment "looks."
You can start with a raw grid or a digital image of your office or home floorplan. As you walk, you click at key points. The software does the rest.
Hover over an access point on the heatmap--routers are neatly represented by a generic icon from the manufacturer, identified by its MAC address prefix--and you see the corresponding heatmap. (The graphic is a fancy icon; it's really only a 2D mapping package.)
A list at left shows a live scan of networks and their characteristics.
When I spoke to the program's product manager a few weeks ago for this article in Ars Technica, he said that the intent was partly to provide an up-to-date scanning package to replace NetStumbler, which has been out of development for years.