I've been building exactly this: http://browserlocation.co/ http://browserlocation.co/ I have a JS library coming also for use when the w3c geolocation fails.

I've been building exactly this: http://browserlocation.co/ http://browserlocation.co/ I have a JS library coming also for use when the w3c geolocation fails. The data is open and downloadable with cities etc (CSV right now). There's a mailing list for updates, and anyone can contribute just by opening the website in a browser!