Hi to all.
I'm writing this post about a solution that I've found for generating a standard compliance Google Sitemap for Drupal 6.x, 7.x multilanguage sites.
Because I was not very happy and satisfied with any Drupal Google Sitemap modules, I've written a script that you can simply upload in the root of your site for generating automatically a google sitemap for every menu link and for each node, with multilanguage prefix if needed.
The basic difference that I've found between any other scripts that I've seen all around is that I've followed the database approach, instead of scanning pages link-by-link like a crowler: I've made a matching between "node" and "menu" with "url_alias" drupal database tables and, for example, this is a result:
<url>
<loc>
http://www.yoursite.org/it/this-is-a-test-content/
</loc>
<lastmod>2009-05-20</lastmod>
<changefreq>weekly</changefreq>
<priority>0.8</priority>
</url>
The "node/NID" is served when a content hasn't a url alias and the prefix "/en/" is not inserted for the english default language.
I've specified "priority" to 0.8 and "changefreq" to weekly for the nodes and "priority" to 0.9 and "changefreq" to monthly for the menu links, but you can easily change this in the source code.