It directs users to the ICCP Foundation, whose website is down at the time of writing, but can still be viewed in Google's cache. It claims to be a law firm targeting filesharers based in Switzerland, and warns that offences could result in five years in prison and a $250,000 fine. Users are given the choice to refer the offence to court or immediately pay $400.
If you choose the court option, you get a notice that says: "Performing this action is construed as refusal to co-operate with the copyright holder and unwillingness to consider pre-trial settlement. If you continue, all the data gathered will be passes (sic) to copyright protection organizations and to the court. We recommend cancelling this action and choosing the option "pre-trial settlement".
The foundation claims to be affiliated with the RIAA, MPAA and the Copyright Alliance, and its software seems to scan you hard disk for .torrent files to display as evidence to scare you with. Of course, if you're using magnet links, it won't find any. Still, if this screen starts appearing for you, then you might want to reconsider what you've been downloading - for security reasons, as well as copyright ones.