Three popular websites that publish movie lists in alphabetical order are BoxOfficeMojo.com, Wikipedia.org and Phi-Phenomenon.org. IMDB.com also contains a huge database of movies, but as of November 2015 there is no option to sort the entire database in alphabetical order.
To find the lists, the first option is to navigate to BoxOfficeMojo.com, and under Indices click on Movies A-Z. The second option is to navigate to Wikipedia, search for "List of Films," and click on the Alphabetical Indices link on the resulting page. The third option is to navigate to phi-phenomenon.org and click on the Alphabetical link in the sidebar.
Box Office Mojo also lists the studio, total gross, opening date, opening gross and number of theatres for each movie. Phi Phenomenon lists the opening date and direction of each movie, in addition to a rank for the movie based on the site's movie ranking system. Wikipedia only lists the opening date for each movie. Wikipedia consolidates all movies that start with a certain letter into one page, while Box Office Mojo further categorizes the movies based on the second letter in the movie title.