As you may or may not be aware each website has a sitemap.xml file which was primarily used by Google Webmaster Tools. Other search engines now support this format and a lot of them use the 'open-format Sitemaps protocol' which is the format we put our sitemaps in.
We have added a line in each websites' robots.txt file that will show the location of the sitemap.xml file to any search engine which supports this format.
