If I may plug my own site (which was my favourite site on the web before I started actually working on it! Why do you think I'm part of it now?), u2-vertigo-tour.com's database could have easily answered this question for you.
Discotheque has been played twice on tour, 2005-09-17 in Toronto and 2005-09-20 in Chicago. No other Pop songs have been played yet but Mofo is rumoured. Odds are Discotheque will return either tonight at Boston II or during the NYC five show run.