I've successfully created some test pages using the Fancybox library.
However, when I try to integrate the library into the main site, instead of opening up an image in the modal window, it opens it in a separate tab/window/page.
The successful empty test is here: http://www.halal-helvetica.ch/kash.html
To get to the one that doesn't work, you need to go to: http://www.halal-helvetica.ch/index2.php, then search for Bern. Then click on the icon for a restaurant, and then click on the small grey square in the info area on the left of the screen. When you click that, you'll see that it opens up a large grey square in a new page instead of in the modal window.
I hope i've been specific enough.
Thanks Kash.