Sitemaps provide a means by which webmasters can inform and direct spiders, they help Google and other search engines to index more pages and discover new content more quickly and effectively. They are also useful for ensuring that all your pages are found and indexed.
Submitting a sitemap to Google is free and simple to do. Ideally you should create your sitemap in XML format, once it has been uploaded to your domains root directory you can submit it by loggin into your Google webmaster tools account. Remember that you will need to update the sitemap and resubmit it everytime you add, delete, or move pages in your website.
A sample Sitemap containing just one URL and using all optional tags is shown below. The optional tags are shown in italics.
<?xml version=”1.0″ encoding=”UTF-8″?>
lastmod: This displays the date this file was last modified.
changefreq: Frequency that the page is updated.
priority: Here you can select the priority you want Google to give to spidering that page on your domain. A priority factor of 0.0 would be minimal and a priority factor of 1.0 would be the maximum. This factor is ONLY relative to your site and will not affect your rankings.
Google has provided a detailed helpfile on how to create XML sitemaps here:
The most simple way of creating a sitemap is by using one of the many free sitemap generators available online such as: http://www.sitemapspal.com or http://www.xm-sitemaps.com although as these sites tend to charge for sitemaps of over 500 pages, larger site owners may wish to use the free and excellent Xenu Link Sleuth.