JQuery modal popups are a pretty common usage of JQuery which has a large plugins library. The article seems to be from 2009 and is now a couple of years old. The JQuery plugins library is normally at
http://plugins.jquery.com but, because of technical difficulties, is now at
http://archive.plugins.jquery.com.
So a JQuery modal plugin that I have liked and played with is here
http://www.ericmmartin.com/projects/simplemodal/ and a search for other plugins is here
http://archive.plugins.jquery.com/search/node/modal.
HTH,
fg