Google XML Sitemaps
Google XML Sitemaps is a plugin that creates an XML sitemap for your WordPress site, that serves as a road map for search engines so they can reliably and effectively crawl all the content on your site. The plugin is simple to use; all you have to do is install it and activate it. The plugin does the rest. You can download it from http://wordpress.org/extend/plugins/google-sitemap-generator/. After installing the plugin, you'll want to register your sitemap by logging in to Google Webmaster Tools at http://www.google.com/webmasters/ and navigating to Crawl and then Sitemaps.