is there \a piece of software of script that i can install on my website that automatically creates an XMl sitemap? thanks
To get started I'd use an offline generator like the GSiteCrawler. Once you understand the basics you can swap to one of the on-server solutions (depending on your site, Google has a whole list of third-party sitemap generators or check here: http://www.smart-it-consulting.com/article.htm?node=163&page=113 )