Google's own resource for SEO and site architecture. Get it straight from the horse's mouth
http://googlewebmastercentral.blogsp...ter-guide.html
Free sitemap builder. It crawls your site and creates an xml, ror, or html sitemap
http://www.xml-sitemaps.com/
NOTE: this is great for static sites.
If you have a WP blog, use this xml sitemap builder for WP
http://wordpress.org/extend/plugins/...map-generator/