In this tutorial Alex from Good Web Practices discusses how to create a 'Lightbox' effect on your Joomla 1.0 or 1.5 website using the YOOeffects from YooTheme.

Using a Lightbox is a great way to show off your images on your website, as a slideshow or for individual pictures. Videos can also be shown using the Lightbox javascript - both from your own website or streamed from another site (such as YouTube).