"The ultimate Warchalking accessory: the credit-card sized WiFi sniffer from iDetect that can tell you with the press of a button whether a wireless networks is present. Nice, but a Pocket PC with Mini Stumbler installed is even better, since it can identify multiple networks and tell you how strong their signals are." [Gizmodo]

I'd like to see something like this built-in to devices - a light on my PDA that blinks in a Wi-Fi zone (even when the PDA is off), on my laptop's card, or even on my cell phone. One less thing to carry. Unfortunately, I don't see a price listed anywhere.