Simply put, an XML Sitemap (or site map) is a list of pages that you have on your web site. You can submit an XML Sitemap to Google's Webmaster tools to assist Google in finding pages on your site.  Sitemaps are helpful in letting the web crawlers know what pages you want indexed.  There may be pages in the list that might be overlooked by normal web crawling methods.  Such pages may not be linked to within your site or not in your main navigation.

You can create a simple Sitemap with the format in this example of sitemap.xml:

<?xml version="1.0" encoding="UTF-8"?>
     <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
      <url>
          <loc>http://responsive.zemplate.com/responsive-intro.php
          <changefreq>monthly</changefreq>
          <priority>1.0</priority>
     </url>
     <url>
          <loc>http://responsive.zemplate.com/ipad-landscape.php
          <changefreq>monthly</changefreq>
     </url>
     <url>
          <loc>http://responsive.zemplate.com/ipad-portrait.php
          <changefreq>monthly</changefreq>
     </url>
     </urlset>

Call the file sitemap.xml and place it on the root directory of your site. It is good to update your sitemap.xml frequently as your content may have changes, new pages added, pages deleted, etc.

Notes:

  • The Sitemap must be UTF-9 encoded.  Simply put - don't create the sitemap in Microsoft Word or another word processor.  Create it in Notepad or a simple text editor. For special characters - you must use UTF-8 encoding. Learn more about UTF-8 encoding here. 
  • You must include the entire url including http:// (or https://, etc) and if you chose to use the www. format, keep it consistent throughout the document. Use is on every url.
  • You should break up very long Sitemaps into smaller documents and provide an index for your sitemap pages. A Sitemap index file can only specify Sitemaps that are found on the same site as the Sitemap index file.
  • You don't have to use .xml formal, you can also provide Sitemaps in RSS (Real Simple Syndication) 2.0, Atom 0.3 or 1.0 feed.  You may also provide a simple text file with one URL per line.  See the guidlines at www.sitemaps.org/protocol.html
  • Sitemaps can be placed on the root of your website, it is suggested that you do so, but you can have them in a sub-directory.  Those placed in a sub-directory can only list urls of files that are in that sub-directory.
  • You can also specify the location of your Sitemap in your site's robots.txt file.

Your Sitemap can be created manually using a text editor or you can use a free third-party site such as xml-sitemaps.com

Your Sitemap can be just a listing of pages, but it can also provide specific information about the content on those pages such as images, videos, mobile, News and software source code.  The Sitemap can also provide modification dates, how frequently content on the page is likely to change, the priority of the page in relation to the other pages on the site. 

To submit your Sitemap to Google, you should signup for a Google's Webmaster Tools and submit your sitemap using their system.

You can find out more about sitemaps and the specific requirements for submitting to Google, refer to Google's webmaster tools by clicking here.

Extensive information can also be found at sitemaps.org.