You need permission - a license - from a movie's copyright holder. In some cases that's easy. For example Hulu.com has movie trailers with embed codes that have been provided by the movie owners, so you can legally embed those trailers on your web site (the drawback being that I believe they can only be viewed from US IP addresses). Also, many official web sites for movies (particularly indie pix) have video or other multimedia content you can embed. And once you establish yourself as a significant review site, movie publicists may hook you up with content, which is what happens on sites like Aint It Cool News and Bloody-Disgusting.com. But notice that even on those popular sites, many of their reviews aren't illustrated with trailers. Until you are established, you may have to limit yourself to just linking to trailers of the movies you are discussing.
You do not need permission of any kind to write a review of a movie. To have access to promotional materials, like posters, images, and trailers, you should contact the companies distributing the movie to get rights to use those materials.
You don't need any permissions to review movies. It's your personal opinion, and I think they will even make money from you if you put up advertising for their DVD's or whatever. If you get big enough (like making hundreds of thousands of dollars per month), then you may try and get licenses or make a contract...
Reviews are personal opinions, I would imagine you don't need a license for reviews. Like stated, you'd only need one in a instances where you use actual material from a movie.
Well if I dont other people to take credit for my reviews I can copyright my material correct? How would i do that?
as usual nobody ever mention PHOTOS. the OP will jump on his seat when he'll discover that he needs to BUY an RM licence for each of the movie-cover posters from macrostock sites that means from 5$ up to 300$ each. yes, you heard it well, it's not free and it's not cheap. then open up any movie blog and not only they steal movie covers but even screenshots of the movie itself... the web is 99% piracy ! fact.
copyright is yours in any case in the moment you CREATE an opera. if your content is just scraped article, stolen images, links, and user generated junk, well i guess there's nothing to copyright about it. by opposite if you wrote long reviews for each movie and signed them all with your name and surname (no nick names!) it IS your (c) copyright and always will.
There is a question about fair use. If you use a publicly promoted image for your review, it's arguable that fair use might apply. Moreso, there is little motivation for the studios to sue. Once you go beyond a story, then you've got issues. For the most part, these reviews and the content used are innocuous. Nobody will argue the issue if what you're doing doesn't involve ripping someone else off from money they hope to recover.