Perhaps it’s just a reflection of the post-bubble zeitgeist, but there’s been much ado lately about the Museum of the Phantom City app for the iPhone, from BLDG BLOG to Urban Omnibus all the way up to the Times. Admittedly, who doesn’t love a nice iPhone app (not that we would know personally…) especially one that allows you to navigate the city that could have been—at least if architect’s ruled the world—in real time and space. Developed by the two-man firm of Cheng+Snyder as part of the Van Alen Institute’s New York Prize fellowship, the app uses the phone as a tracker to pinpoint unrealized projects, usually of a highly theoretical persuasion—John Johansen’s Leapfrog Housing, Michael Sorkin’s Brooklyn Waterfront, THINK’s World Trade Center proposal. If this all sounds terribly confusing, either download the app yourself, or better yet, meet up with Chen and Snyder in Bryant Park from 2:00-4:00 on the phantasmagorically appropriate day of October 31, where they’ll give a full tour of the museum, so to speak.