A Sitemap is a very important page of every Blog, whose function is to inform the Search Engines about all the URLs on a website that are available for crawling and how often they get updated. Tecnically, a Sitemap is an XML file that shows all the URLs for a site and is updated every time you create a new article. This allows search engines to spider the site more intelligently and better. To create a Sitemap for your WordPress Blog, you will need the XML Sitemap Generator for WordPress.
You can download it from the WordPress Plugin Directory for free. This WordPress plugin will create a compliant sitemap in the format supported by most Search Engines, including the most popular ones, Google, Yahoo and Bing. Like I said above, Sitemaps are very useful because they give valuable information to the search engines.
They will know how often to scan your site, which pages are more important, which have a lower priority, etc. The advantage of using Sitemaps is that you are able to view reports on crawl results and statistics. You’ll also see the most used search queries to find your site and the search queries that get the most clicks.
First, I recommend to build your Sitemap and then submit it to Google Webmaster Tools here. Make sure you verify it following the steps on that page. Make sure to identify yourself as the owner of the site and to validate your submission.You can also submit it to Yahoo here. For both services you need a Google and Yahoo accounts. If you don’t have one yet, make sure you sign-up. It takes only 5 minutes.