The XML Sitemap module creates a XML sitemap in accordance with the
Sitemaps.org specification.

The module maintains a short change history for nodes in order to better
approximate the change frequency. It calculates the relative priority of
each node based on node type, number of comments, and promotion. It can
optionally submit your sitemap to Google (support for other search engines
will be added once they support the ping interface) whenever it is changed
and can log when your sitemap is downloaded by a search engine.

This module was originally written as a part of the Google Summer of Code
program.

WWW: http://drupal.org/project/gsitemap