Visit the Internet Movie Database website and enter the movie name in the search box. When the movie page displays, click on the "Alternate Versions" link. When the alternate versions page displays, it lists if there is an unrated version and what is included in it. There is also a link to purchase the unrated version.
Search a DVD site, such as IGN Entertainment's website. Enter the movie name in the search box to display results. Narrow your results by including "unrated" in your search criteria.
Find an online forum related to the movie. Post a question about finding the unrated version of the movie or search around to see if someone else has asked the same question, and if they received an answer.