We must submit sitemap file(s) location to Google webmaster tools in order to get indexed by Google search. Initially I generated an XML file through http://www.xml-sitemaps.com/ and http://sitemap.xmlecho.org , uploaded as a file(sitemap.xml) in to my site and then submitted that URL (http://sites.google.com/site/nraveen/files/sitemap.xml ). Google webmaster reported errors and could not index my site URLs. Finally I found that Google sites has an inbuilt sitemap located at …/system/feeds/sitemap. We have to submit the URL as follows http://sites.google.com/site/nraveen/system/feeds/sitemap. Within few hours my site got indexed.