No, not a website! Apple has released an app to preview upcoming movies in the vein of Movies Now. Featuring the same previews you'd find at iTunes Movie Trailers on the web, the iOS app allows you to preview beautiful movie posters, find movies at local movie theaters (either by theater or by movie), and check on upcoming releases by previewing a built-in calendar. Per trailer, movie details can be reveleaed that contains the cast and synopsis for the films you're interested in seeing. You can tweet or email to share, or add the film to your favorites for later recollection.
You can download the universal application from the iTunes App Store for free. More screenshots past the break.