After looking and trying for a good, easy extension for lightbox or similar FX, finnaly I could found this one. I'm not kidding, I've been using Joomla for 4 or 5 years and other extensions requiere something more complicated to make 'em work. This one is just -1 Install -2 Publish Module -3 Link something in your content and add the rel "shadowbox" via text mode edition or inside the WYSIWYG editor.

I love this extension. By the way. V. 1.4 is already on their site and no registration required to download it.