Navigate to trailers.apple.com in your Web browser to view iTunes trailers online. Click a movie icon to access its page and then click a trailer from the list in the column on the left. ITunes offers up to three or four trailers, depending on the movie.
Open iTunes on your computer and click the link for the iTunes Store in the left column to view trailers through iTunes. Click the "Movies" link at the top of the iTunes Store window and then click a movie to access its page. Click the "View Trailer" button to view the trailer.
Tap the iTunes app on your iPhone, iPad or iPod Touch and then tap the "Movies" link. Tap a movie to access its page and then tap the "View Trailer" button.