Gareth has an iPod Touch, which he’s just updated to firmware 2.0 (at even more cost – and that he’s not best pleased about…), which adds many of the iPhone’s location-aware services. The Touch, of course, lacks any 3G/GSM circuitry and bluetooth – leaving only WiFi for position acquisition. Even though my name-server at home doesn’t contain any geographic records, his Touch was able to instantly plot the specific location we were.
This information can’t accurately have been gained directly via the WiFi connection (could it?), any location-based services which use public IP addresses aren’t, I’m fairly sure, that accurate… which makes me think that the only way this can have worked is for the Touch to have broadcast (via Rendezvous/Bonjour) a request for location data, which my iPhone then provided.