Razor port of the locator package: http://our.umbraco.org/projects/backoffice-extensions/locator-package ( + updated to use google maps api v3, no more api keys)
It works in combination with the google maps datatype so you’ll need to make sure that your documents have coordinates stored before you are able to search (so a property of the type google maps using the google maps datatype).
Full details here: http://www.nibble.be/?p=105