The Google Sitemap Protocol
"The Sitemap Protocol allows you to inform search engine crawlers about URLs on your Web sites that are available for crawling. A Sitemap consists of a list of URLs and may also contain additional information about those URLs, such as when they were last modified, how frequently they change, etc."Also, you can use gzip to compress your Sitemaps, and there is an XML schema that can validate my XML Sitemap at http://www.google.com/schemas/sitemap/0.84/sitemap.xsd, and a schema for Sitemap index files is available at http://www.google.com/schemas/sitemap/0.84/siteindex.xsd.
Evil brainfart (Lazy Web Request) : could/would/should you use the SiteMap xml file, transform it, using XSLT, and produce your human readable sitemap? How about transforming it to produce a RSS feed? Any other brainfarts?
That was quick (or I am slow?) : Google Sitemaps for Wordpress
update: SlashDot has picked it up. (I must be getting lazy cause I didn't even think of submitting it). Darren Foot spots an execution gap (and a opportunity) for a "Generator my Sitemap for me" site/utility. And I'll note (via the Google Blog) a call for a Sitemap Generator for Lotus Notes hmm..
Also Google Sitemaps in Movable Type
Update June 8th: Dave Winer makes some good observation and a great sugestion that Google should use an existing HTML element :
to note the files location.
<link rel="sitechanges" type="text/xml" href="http://www.myfoo.com/mancuso/mychanges.xml">