..oooo, its like a movie! Matt Mullenweg, the lead developer of WordPress has announced the release Akismet (go the name!), a free WordPress remote spam filtering service. You enter your WordPress.com API key after installing the plugin on your own blog and away you go! Best of all, comments that are marked are held in the moderation queue for 15 days before being deleted (assuming you login to WP every once in a while.) Freaking awesome!
(Doh, I spelt the name wrong!)