To Do: Google Sitemap
Arne Brachhold has developed a plugin for WordPress that automatically generates Google Sitemaps.
Google Sitemap Generator for WordPress v2 Final
Not sure that WordPress necessarily needs a sitemap generator, as the built-in Permalink system is already pretty good. A human readable sitemap generator could be useful for larger sites though.
What I really need to do is build something I can use with the ColdFusion site I look after. That system was built before the blog buzz, and really isn’t well geared towards SEO. I think that the Google Sitemap tech will be most useful for these older sites.