Get your physical location based on the MAC address of your WiFi access point (Mac OS X only)

getlocation.sh

/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -I | grep BSSID | awk '{print $2}' | sed "s/^\(.\):/0\1:/" | sed "s/:\(.\):/:0\1:/g" | sed "s/:\(.\):/:0\1:/g" | sed "s/:\(.\)$/:0\1/" | xargs -I{} echo 'curl -s http://www.google.com/loc/json -d '\''{"version":"1.1.0","request_address":true,"wifi_towers": [{"mac_address":"{}"}]}'\'' | awk -F\" '\''{print "{} = "$32" "$36", "$28", "$12}'\''' | $SHELL

This one-liner uses/emulates the Google Gears API. Something similar could be done by using the Apple implementation of BSSID detection, which does a POST to http://mac-services.apple.com/clls/sloc. The format of the POST request and response is unclear to me though.