Though tempted, I'm yet to pick up a WiFi detector; tales of disappointment where promise-everything gadgets turn out to only be good at locating microwaves, cordless phones or - worst of all - secured networks have put me off. Canary Wireless have another to try to persuade me, though; their HS20 uses a true 802.11 chip, meaning it won't be confused by WiFi-alike signals, it has a screen to show security status, and it'll be cheap at just $59.95.
Capable of sniffing out b, g and n flavours of WiFi, the HS20 measures 2 x 3 x 0.5-inches, weighs 2oz and runs off two standard AAA batteries. The 96 x 64 display may be small, but it's backlit and the scroll keys on the side page through different SSIDs, channels, WEP/WPA status, signal strength and more. Alternatively, there's a "quick glance" screen option, where simple icons indicate the presence of locked or unlocked networks.
It's expected to be available sometime in Q1 2008.