Google Testing Sitemaps

BetaNews | Google Testing New Indexing Approach
Since its inception, Google has tried to make sense of billions of Web documents and using advanced in-house technology. But now, Google is experimenting with a new concept to better its search crawlers: ask webmasters for help. The program, called Google Sitemaps, could revolutionize how the Web is indexed.

Specifically, Sitemaps will direct Google’s Web crawlers to content that has been changed or added, removing the need for Google to spider an entire site. Sitemap files are based on XML and contain a number of parameters to aid in the search indexing process.

The Google Sitemaps FAQ is here.