Google Sitemaps

Here's some pages that I've found useful - the main site is Google's own, which is here where you can manage your sitemaps (resubmit when updated), and get stats about the site. This site has an easy way to get the most recent updates from your site (using your RSS feed). http://sitemap.xmlecho.org/ can generate a complete sitemap for you and help you get it setup on your webserver very easily (and even submit it to google for you) so is definitely worth checking as well.