Pop-up Messages

How can I create pop-up messages in WP? I know how to use the Alt Text with a blank URL so that when people hover over a link they see the alt-text and if they click on the ‘link’ nothing happens. But sometimes I want the message to stay longer and let the user have the option to close the message.

I have a cooking blog, http://www.cookswell.com and the message may be as simple as explaining a term I use or why I use a particular ingredient in my recipes.

I know how to do this with Dreamweaver MX for my regular web pages and I know DW uses Java to perform this function. Any ideas on how to do this in WP?