Wow. Just got a new phone, google g1, currently exclusive in the uk to t-mobile. Just because I can, I did a wi-fi scan last night on the way home. In less than 2 miles, through a small rural town, I found 92 wireless routers. 11 of them were open. The saved kml file brings them all up on google earth in seconds. What fun you could have!
p.s. posted from the phone.