Hello together, we have now: http://meta.wikimedia.org/wiki/MediaWiki:OSM.js
So to install the OSM-map in WP you need only to insert the following script inside your Wikipedia and modify the first two lines:
var osm_proj_map='mapa'; //"map" in project language var osm_proj_lang='pl'; //project language
if (wgServer == "https://secure.wikimedia.org") {var metaBase = "https://secure.wikimedia.org/wikipedia/meta%22;%7D else {var metaBase = "http://meta.wikimedia.org%22;%7D
importScriptURI(metaBase+'/w/index.php?title=MediaWiki:OSM.js&action=raw&ctype=text/javascript&smaxage=21600&maxage=86400');
Greeting Kolossos