Downloading the latest movie "free" from file-sharing sites is not only illegal but highly dangerous. Content often includes viruses, criminal malware and other dangerous software. Law enforcement agencies and other, less reputable sources heavily track those who use the sharing software for these sites.
Intellectual property rights are evolving, and firms affected by the illegal downloading of movies are pursuing every avenue to limit their losses in this area. As several law enforcement agencies currently track IP addresses of those who use file-sharing software, such as BitTorrent, even a single use may lead to unforeseen consequences further down the line.
There are many reputable sources for legitimate and free films, however. The Internet Archive, Retrovision and Uncle Earl's Classic TV Channel are some sites that host many classic movies that have entered the public domain. This means their copyrights have either expired, or the owner of the movie rights has released them to the public.