I just got my latest cyberguys catalog today and spotted this.
Trendnet USB Hot Spot WI/FI Finder

Would the wifi radio work when plugged into a Zaurus?

Use this compact wireless hotspot detector with built in 802.11 b/g connectivity to quickly locate wireless hotspots without booting up your computer. The hotspot detector displays a host of information about available wireless signals including signal strength, network name (SSID), encryption type, channel, source and battery Life. Best of all, it's also an 802.11g USB 2.0 adapter so you can just plug it into your laptop to connect to 802.11b/g signals you've located. Includes drivers on CD-ROM. Requires Microsoft Windows 98SE/Me/2000/XP/Vista.

Hotspot Finder displays SSID, channel, security enable/disable and signal strength information
Built in Li-Ion battery recharges when plugged into USB port