FYI, I have just commited a preliminary version of a GEO mode (location management, if you will) to CVS HEAD. You will have to set "$wgUseGeoMode = true ;" in LocalSettings for that to work.
Currently, it does not do *that* much: It uses the ISBN mechanism, but with the GEO keyword, like "GEO 1.22.33:-4.55.66". This is converted to a link to a "SpecialGeo" page, which currently only shows a link to the according MapQuest page.
As a special option, I hard-coded a regular expression search-and-replace that will work on the RamBot articles (like "38°30'10" North, 90°38'42" West"); coordinates on these pages will thus be linked likewise.
At the moment, it does *not* store the coordinates/article data pair in a special database table, which will be required for "real" functions, like "what's near this location". I might implement that later, unless someone beats me to it (hint! :-)
Magnus