Export Google Sites

"Google's Data Liberation team built a Java application for importing and exporting Google Sites. The application lets you export the pages from a site and all their attachments to a folder.

"The folder structure of an exported site is meant to mimic the Sites UI as closely as possible. Thus if exporting to a directory "rootdirectory," a top-level page normally located at webspace/pagename, would be in a file named index.html, located in rootdirectory/pagename. A subpage of that page, normally located at webspace/pagename/subpage, would be in a file named index.html in rootdirectory/pagename/subpage. Attachments are downloaded to the same directory as the index.html page to which they belong," mentions the user guide."

http://googlesystem.blogspot.com/2009/09/export-google-sites.html