ThickBox

Allows you to embed ThickBox into your blog. Simply insert ThickBox compliant markup
where ever you want and you’re all set. It is a pretty lightweight plugin but here
are some of its features:

• comes with an expert mode that allows you include the JavaScript and CSS for ThickBox only on those pages that actually need it
• you can opt to use the script and style already bundled with WordPress
• automatically adds the correct class attribute when using the gallery shortcode
• and also contains SmoothBox

Licence

This plugin is released under the GPL.