Patrick H. Lauke (recenter) made a "GeoURL backwards" Firefox extension. If you install it, it'll light up a little GeoURL globe when the page you are on has ICBM headers. If you click the globe you get sent to see a list of sites nearby. It's really clever.
You can install it by clicking here: http://www.splintered.co.uk/extensions/geourl_0.2.xpi
update - It's now listed on addons.mozilla.org
update - someone else made another 1.5 extension.
Firefox will show a warning at the top of the screen, to proceed click "Edit options" and then "Allow" in the dialog that comes up. That'll make Firefox trust Patrick's site. Click "OK" and then click on the link to the extension again. When the extension has been installed you have to restart Firefox and then get the extension active in the toolbar by going to the menu "View" - "Toolbars" - "Customize" and then drag the GeoURL icon up to the toolbar. Whee, that was a lot of work. But try it, you'll like it.
update - Mark Zeman made a flickr world map extension based on the GeoURL extension.

