A site map is something that every website should have to help them obtain high rankings on the SERPs.Search engines use sitemaps as a guideline when crawling your site, so that to ensure that they don't "miss" any page.Please note that i am talking about crawling your site , not indexing.
You cannot force google or any search engine to Index a page but you can force them to crawl asap(expecially when you just added new content to site.Then based on the search engine algorithm , your site will show/disappear from search result.

Sites that generate sitemap for your site for free
Code: 
http://www.xml-sitemaps.com/
http://www.web-site-map.com/
After you create/update a sitemap , upload to your host.Then open google webmaster tool and submit the latest sitemap.

Hope it helped you
Ifirst Reviewed by Ifirst on . [Tutorial]Why a Site Map Is So Important for SEO A site map is something that every website should have to help them obtain high rankings on the SERPs.Search engines use sitemaps as a guideline when crawling your site, so that to ensure that they don't "miss" any page.Please note that i am talking about crawling your site , not indexing. You cannot force google or any search engine to Index a page but you can force them to crawl asap(expecially when you just added new content to site.Then based on the search engine algorithm , your site will Rating: 5