Hi Chanan Zass,
Please take a look at the following forum thread - Flash Menu from Navigation XML
as it explains how to get pages from the site map and write them to an XML file. So our suggestion would be to use this method in a web service in order to constantly get latest version of the site map.
As for localization - we the pages pave LanguageVersions property that returns an IDictionary holding a reference tho the language versions a page has plus that pages. You can get the culture IDs of each language version of a current page:
> languageVersions = page.LanguageVersions.Keys;
All the best,
the Telerik team