Instead of running a general Google or Bing search, try some of these websites selected by your professors and librarians for their particular usefulness and reliability. They aren't necessarily the most popular sites, so they might not show up very high in a page of search results.
It's hard to tell whether online journals are reliable enough for scholarly research -- those listed here pass the mark. Don't hesitate to consult with your professor or a librarian to determine whether a particular source is appropriate to cite in your research.
Citing your sources properly -- especially the films that you refer to and any images you include in your paper -- is important and required.
Purdue University's OWL Writing Lab Citation resources are the best ones out there on the web. Generally, Film Studies courses require that you use MLA style. Detailed information on MLA and other styles, such as Chicago, are available here.
Check out Berkeley's Guide to Citing Film, Video, and Online Media.
Diane can help with citations, too!
Academic Journals
Movie Footage
Box Office and Script Information