Apart from very powerful servers and hosting you would also need guys who can develop it for you. Ohh I missed the most important part of it which is License to show those movies.
It would cost so much. Once there was a site named stage6.com. It is owned my Divx Labs. In that the users hosted lots and lots of copyright contents, and they got no problem with that for some time. When the number of users reached a certain level some raised voices against it. And due to it and lack of maintainer made the company to close that site 4ever. So think twice b4 hosting a site like that. If u have all the support and if u can host ur site even from a backup location then step ahead. or else its not a good option.