WordPress Theme Viewer – Collection of WordPress themes with a graphical and textual preview available for each theme. Sorting and search feature as well.

WordPress Theme Site – A website where people can share their WordPress themes. Free uploads and downloads (uploads require registration). Over 1600 themes.

WordPress Theme Designer – Website with many magazine styled WordPress themes that are monetized for good Banner Ad Integration.

WordPress Theme Design and Consulting – Custom WordPress themes and general blog consulting. Includes tips for theme design.

WordPress Plugins and Themes – WordPress Plugins and Themes available for free download.

Using Themes – The official WordPress codex help page for using themes.

Top WP Themes – Download quality and professionally designed WordPress templates for free. Also allows user ratings of themes.

Themes Pack – A collection of free WordPress Themes from various styles.

Themes Junction – A website with many free wordpress templates.

Simple WordPress Themes – WordPress theme site featuring third party themes. Each theme posted has a thumbnail preview, download link, and demo where available.