The free movie world changes quickly, with companies starting up, folding, or being absorbed by other groups, so you'll need to keep tabs on what's current and what's not. However, there are many sites where you can stream free movies online.
Sony owns Crackle, and this website has hundreds of film and television offerings online, free to watch and simple to access. There are some commercials, but the selection is worth it.
Vuze is a bit torrent app that allows you to download movies. Look for the frog icon to make sure the content you downloaded is legal.
There are millions of public domain movies on this internet resource. They have musicals, comedies, and other feature-length films, with many of them from the golden age of cinema in the mid-20th century. Look for Sherlock Holmes, Dracula, and other classics, including the original Night of the Living Dead.
This website is part of major cable provider Comcast, so you have to be a Comcast client to access everything. But if you are, then you will have more than 150,000 choices for entertainment.
If you're a fan of cult classics like Attack of the Giant Leeches or Last Man on Earth (the original, with Vincent Price), Veoh is a destination you should bookmark. The Veoh website offers movies from days gone by for your enjoyment.
Entertainment Magazine Online
Specializing in motion pictures released by major companies from 1910 to 1960, Entertainment Magazine Online offers movies that are in the public domain and are completely legal to download. Many black and white classics will provide days of exploring the best of early film, including silent features.
YouTube has thousands of videos: short, full, length, and all free. While films are carefully vetted for copyright infringements, you can find lots of documentaries (like The Making of Alien), and classics (Carnival of Souls) that are full length and free. Some of them have been broken up into chapters, while others run full length.
You can find recent and popular films at this website, including Benjamin Button and Flashdance, but there are some really fun and cheesy horror films to entertain you on a dark and stormy night.
This site is more like a social network for film lovers, and while the movies are unusual (Honor Flight, L.I.E.), you will also find the East Side Kids and other nostalgic flicks. Easy to use and a great resource for filmsters.
Classic Cinema Online
If you enjoy great stars, action, and cliffhangers, Classic Cinema Online has hundreds of films for you, from Hold that Ghost (Abbott and Costello) to The Lady Vanishes (an early Alfred Hitchcock.) This site is run by a dedicated individual, so selections may be added sporadically but for film buffs, it's a treasure chest.
Movies Available for Streaming and Downloading
When you stream movies, you watch them over the internet. Many big companies offer streaming services online though you'll often be required to watch a short commercial or two before your movie gets rolling. While you may not find the most recent films, you will find excellent work from documentaries to film shorts, classics, and even anime and cartoons.
Another option is to download the whole movie to your computer. Generally, the free, legal, full-length movies available for download are either in the public domain or are indie movies being offered for free by a distributor. You will most likely not find the latest Hollywood blockbuster on a legitimate movie download site. Instead, you will have the opportunity to enjoy unusual selections, including foreign films.
Beware of Piracy and Illegal Downloading
Before you begin streaming or downloading your favorite movies, always consider the legal ramifications of your online actions. Illegal downloading is at an all-time high, and there are very strict rules on pirating entertainment. The US can prosecute not only the organization offering the movie but also the individual downloading it.
If you locate a site that is filled with movies filmed using a handheld camera or cellphone in a theater, or clips that were "ripped" from a DVD, then the downloads are not legal. Check the site to see if they have an official disclaimer or an information page that further discusses the legalities of their movie downloads. Download sites that offer illegal downloads may be rife with viruses, spyware, malware, and other nasty things you don't want on your computer.
Finding free movies online takes some effort and attention, but once you realize how many great shows are out there waiting to be viewed, you'll spend lots of free time in your own home cinema.