What do you mean you can't start downloading? Is it that
1. You can't find the films you want to see,
2. you always get "could not download" message, or
3. anything else?

If 1., well what can I say. No one's sharing the film you're after (at the time you were saerching, that is). Keep looking. if 2., it could be that the connection is busy. Movies are always in heavy demand. Also, if you don't have a fast connection, the user on the other side could cut you off in order to open the connection for someone else. Also, some users prefer to "trade" when it comes to movies. Usually, it's indicated in the file names (eg. file name including "trade only").

Uploading movies are indeed a timeconsuming thing. Even when you're in T1 or T3, it'll take at least an hour or two for a 400 MB file, and that's provided things go veeeery smooth. Besides, they are risking themselves from exposing themselves to those like RIAA by being online for hours with 400 MBs of transmission. So just keep in mind, when someone allows you to download a movie, they're doing quite a big favour. Nice people indeed.

Anyways, good luck.