Unfortunately, after a site has been shut down on Xanga, it takes some time for Google and Yahoo to take the pages out of their system. If your child's site has already been shut down, the search engines will eventually update their database and the pages should disappear from the search index.  We've very sorry for the delay – and are working on systems that will let us quickly inform search engines which pages to take out of their systems.

More information can be found on Google's webpage here:
http://www.google.com/remove.html

And on Yahoo's page:
http://help.yahoo.com/help/us/ysearch/indexing/indexing-13.html