My favorite thing about open platforms that allow third-party developers to run wild is when those independent programmers actually do. Jeffrey Grossman wrote a free native application called Movies.app that revolves around movie listings and offers everything from from a straightforward, yet sophisticated lookup by movie or theater to a crisp, clear preview on the phone.
Grossman wisely included the other essential information that every moviegoer may want or need, including supporting information on IMDB, a lists of popular movies currently in theaters, and another list of shows coming to theaters soon (first up is Dark Knight). There's also a way to buy tickets on the spot through the iPhone brand of Movietickets.com, and complete Google-powered maps and directions. The only things missing are user reviews and stars for theaters with the best popcorn.
Note: Movies.app currently provides listings for U.S. theaters only. All users may watch trailers and read up on opening flicks.