I did something similar (albeit very rough, and not really finished) in google maps for Australia. A couple of scripts generate the kml file directly from the PDF version of the Australian AIP (could possibly work for other countries too).
Australian Navaids in Google Maps
or grab the kml for google earth..
http://kibbet.com/gmap/navaids.kml
(and ignore my rather bad attempt at doing little icons too)
