I've found a few sites for doing this but most have broken links and/or bad quality.
Here is a good quality link to 300(the movie):
http://www.8thcircle.net/movies/47-3...-dm-embed.html

It is always better to download, but with this you don't have to worry about mpaa or seeding back. It plays instantly if you have broadband as well, so this is perfect for the impatient.

other sites i've found:
peekvid.com
alluc.org

Enjoy!