If its via a torrent site, this depends on the connection you have and also the number of "seeders" - mine is 1mb and if a film is well seeded (number of people and their relevant upload speeds) an average movie of 700mb or so will take about 2-3 hours to download - however these are from sites that depend on people uploading the equivelant amount they download or else people get banned, some of the public trackers have a lot of so called "hit and runners" who download and then dont upload back, so these can be slower.
Plenty of sites around, Sladinki007, piratebay , mininova for example if you google you should come across plenty.