Google launched a free service on Friday that gives Webmasters more control over what Web pages are crawled by the search engine. Until now, the most that Webmasters could do to encourage Google to index their site was to submit their home page to Google and hope the search engine found all pages linked from it. The new service, known as Google Sitemaps, lets Webmasters tell Google about all of their Web pages, how frequently they are likely to change and which ones they want crawled first. Google hopes the service will improve its search results by providing more information about Web content. The service does not guarantee that a site will be included in the index or change how the site is ranked on results pages, according to Google. To use the service Webmasters must submit an XML formatted site list to Google. This XML file can be automatically generated using an open source tool called Sitemap Generator, which is available from Sourceforge. More information on Google Sitemaps is available here.