While the U.S. has been a mixed bag when it comes to letting the RIAA get information from ISPs, the story has been very different in Europe. It seems the music industry in Europe will have to try other avenues for procuring information they don't have access to on suspected file sharers.
The European Court of Justice has stated that ISPs are not required to disclose identifiable information about their customers in copyright infringement cases. This has a significant impact on future copyright cases in the EU, especially since the RIAA works so closely with the IFPI. It doesn't make it law, however, and case outcomes are not predicted by this:
Under Court of Justice procedures, the Court will review the advocate general's opinion. It typically follows the recommendations of the advocate general, but there is a possibility that it may decide to rule differently.
This will probably not have an affect on policy in the U.S., but it is a curious thing to watch. The IFPI is obviously not happy about this, and believes they should have the right to procure private information about people suspected of copyright infringement.