Yahoo just announced an auto discovery of sitemap via your robots.txt. We all know that robots.txt is being recognized by all search engine. All you need to do is put your sitemap location file to robots.txt.

MSN made its announcement also via their blog together with Google.

For example, this site http://www.allseocontest.com have sitemap located at http://www.allseocontest.com/sitemap.xml. So my robots.txt should include

Sitemap:http://www.allseocontest.com/sitemap.xml

If you have another sitemap, like a directory, or subdomain, just include it on robots.txt and it should be auto discovered. Great suggestion and of course implementation by Yahoo. Hope other crawlers check this too!

Update: It seems major search engines, yahoo, ask, msn and google are supporting this auto discovery feature. Great work!