Here am giving few information about site maps.
The Sitemap protocol was originally developed by Google and is offered under the terms of the Attribution-ShareAlike Creative Commons License
All web crawlers recognize the robots.txt instruction, which tells crawlers not to index certain information, so now webmasters can indicate the location of their site map file within robots.txt files. Meanwhile, the Sitemap's official website is now available in 18 languages.
The best and easy way to create xml site map is through xml-sitemaps
Now the latest update is rare collaboration between search rivals Google, Yahoo and Microsoft over site maps has yielded its first result.
The trios have enhanced Sitemap, a protocol designed to simplify how webmasters and online publishers submit their sites' content for indexing in search engines.
Along with the improvements, the vendors also announced that IAC/InterActiveCorp's Ask.com will support the protocol, which thus gains backing from another major search engine operator. IBM also signed up to support the effort.