You can download and install JA Popup Plugin, that will do your work.
<blockquote>JA Popup plugin supports many types of content display using above frame work like ajax, iframe, youtube video, image, slideshow.
Depending on each type you select, you declare japopup tab in your content (i.e. module, article) to {japopup type=”iframe” content=”http://www.google.com” width=”500″ height=”400″ }Load a sample iFrame{/japopup}
You can use may type to load the content
1. ajax: loading external page or html content via ajax method
2. iframe: loading external page or html content via iframe method
3. youtube: loading youtube video
4. image: loading a specified images
5. slideshow: loading a group of images via a slideshow
The best showcase of JA Popup is used in JA Teline III. Visit JoomArt forum for full detailed userguide.</blockquote>