This just announced at the WMW conference….
Las Vegas, November 16, 2006 – In the first joint and open initiative to improve the Web crawl process for search engines, Google, Yahoo! and Microsoft today announced support for Sitemaps 0.90 (www.sitemaps.org), a free and easy way for webmasters to notify search engines about their websites and be indexed more comprehensively and efficiently, resulting in better representation in search indices. For users, Sitemaps enables higher quality, fresher search results. An initiative initially driven by Yahoo! and Google, Sitemaps builds upon the pioneering Sitemaps 0.84, released by Google in June of 2005, which is now being adopted by Yahoo! and Microsoft to offer a single protocol to enhance Web crawling efforts.
Together, the sponsoring companies will continue to collaborate on the Sitemaps protocol and publish enhancements on a jointly maintained website www.sitemaps.org, which provides all of the details about the Sitemaps protocol.