WordPress Themes
Wordpress Themes – Large collection of free WordPress themes organized by category. Themes are searchable and may be rated by users. All themes are testable via live demo links.
Great Reading
WordPress Themes
Wordpress Themes – A collection of free downloadable themes. Site is updated daily.
WordPress Themes by Sadish
WordPress Themes by Sadish – Customizable WordPress themes, some for sale and some available for free download.
WordPressSupplies
WordpressSupplies – A site with free Wordpress themes and plugins categorized by topic and style. Includes a theme viewer to preview themes on a live WordPress installation.