WordPress 3.0.2 is now available as a mandatory security update for all the earlier versions of WordPress.
WordPress 3.0.2 release fixes a moderate security issue identified in WordPress that could allow a author-level user to gain access to some administrator related features of the site. The update also fixes as many as 9 minor bugs and also packs some security enhancements. For full list of updates in the versions 3.0.2, read at WordPress Codex.
To update your blog to to the latest version of the WordPress, either download 3.0.2 version or use the automatic update feature from Dashboard > Updates menu from the administrator’s area in your blog. It is highly recommended that you download this update immediately even if you think your site hasn’t got any untrusted users.