You can download WordPress 3.0, aka Thelonius, right now at WordPress.org, or upgrade directly from your WordPress dashboard.

The 13th major release of the immensely popular blogging software has been six months in the making by more than 200 contributors, and the highlighted new features include:

•    A new default theme called Twenty Ten
•    New APIs that allow for the easy implementation of custom backgrounds, headers, shortlinks, menus (no more file editing), post types and taxonomies
•    A new multi-site functionality that makes it possible to run one blog or 10 million from the same installation
•    A lighter interface
•    Contextual help on every screen
•    1,217 bug fixes and feature enhancements
•    Bulk updates allowing users to upgrade 15 plugins at once

There is also a video tour on the WordPress site that shows all of the new features. An extended review of the new release will be forthcoming, but visit the site now for more details.