XML Sitemaps and specifying their location in your robots.txt file

Sitemaps are an easy way for webmasters to inform search engines about pages on their sites that are available for crawling. Robots usually discover pages from links within the site and from other sites. Sitemaps supplement this data to allow crawlers that support Sitemaps to pick up all URLs in the Sitemap. Using the Sitemap protocol does not guarantee that web pages are included in search engines, but provides hints for googlebot and her like to do a better job of crawling your site.

Specifying the Sitemap location in your robots.txt file

You can specify the location of the Sitemap using a robots.txt file. Simply add the following line:
Sitemap: http://www.example.com/sitemap.xml
The should be the complete URL to the Sitemap, e.g:
http://www.tubal-reversal.net/robots.txt
reads:
User-agent: *
Disallow:
Sitemap: http://www.tubal-reversal.net/sitemap.xml