Hoople - 7:37 pm on Dec 24, 2011 (gmt 0)

The XML version of your sitemap can be served to search engines bots in your robots.txt file thusly:

User-agent: * Disallow: Disallow: /cgi-bin/ Sitemap: http://www.example.com/sitemap.xml

To me you could call the XML file anything as long as the name matches in the robots.txt file. This is also a way to help the SE's reach deep pages with few links.