I think it's javascript...but;

I'm running a little scavenger hunt on my site; and I want to place some images around the site. I'd like it to be able to when they click an image, a diolauge pops up and displays their next clue; any way of doing this?

I've fallen in love with overlib.js - http://www.bosrup.com/web/overlib/ Not your full solution, but part of it maybe.