A collection of some free, legal downloads of dark music I have found.
Give Me Industrial or Give Me Death
The blog Brutal Resonance have made a promise to keep publishing a compilation a month. A very ambitious project and this is the second release.
As the name hints it's focused on industrial music, but it covers a very wide selection of styles so it also includes meta, synthpop, trance and so on so if you want hard core, old school industrial you may be a bit disappointed, but if you approach it with an open mind I think you can find it very enjoyable.