It is a bit of an incredibly grey area, and the shades of grey depend on what country you live in.
It is illegal to upload pretty much everywhere. That one's a given, since you're publishing someone else's content without their permission. Copyright expires (in the US) after 50 years (and 70 most other places) so most of the old monochrome films on here are up here totally legitimately. Downloading them is totally legal. Come to think of it, that means that the first Bond movie's copyright (as released in the US) is going to expire in a little over a year
The grey areas are where downloading is concerned. Strictly speaking, the downloader is not the one violating the copyright, because he's not creating the file. But the file is still being reproduced (at least temporarily) onto his computer, so well... yeah. You can argue that since the file was uploaded, you assume it was done so legally (because in most cases there's nothing to suggest that there's no way it could be legal) but then you're into the whole counterfeit purse scenario.
The laws as they are do not always entirely cover digital media, and that's where most of the clarity problems arise. As far as providing a definite answer, though, the no it's not legal
's that come out are far less murky than the yes it is legal