As annoying as they can be to visitors, pop-up dialogs are a feature that many website administrators are using to help them advertise special offers or get readers to subscribe to their content. Since it uses pop-up dialogs in its own administrative pages, WordPress comes bundled with a jQuery script called ThickBox that can be used to display these types of dialogs.
This recipe shows how to load the ThickBox script and use it to render a pop-up dialog.