And legal too! As of Jan 21, 2009, Canada’s National Film Board (NFB) has opened up an online screening room of 700 films representing work from all regions of Canada and going back to 1928. One hundred more titles will be added in the near future with an additional ten each month. See the article by Kris Abel about the announcement or just go directly to the NFB Screening Room.
Or if you are looking for world cinema, try the Internet Archive moving images area where you can find such gems as Night of the Living Dead and Reefer Madness.