This plugin gives you a flexible and aesthetic lightbox solution for just about all media links on your website. Easy FancyBox uses the packed FancyBox jQuery extension and is WP 3+ Multi-Site compatible. After activation you can find a new section FancyBox on your Settings > Media admin page where you can manage the plugins options.
Basically, it is a fancy way of presenting images, movies, portable documents and inline content on your website. For example, if you have scaled-down images in your posts which are linked to the original large version, instead of opening them on a blank page, FancyBox opens those in a smooth overlay.Demo Download Plugin