The RIAA can't force ISPs to divulge the identities of their music sharing customers:

Music industry piracy subpoenas illegal - (United Press International): " WASHINGTON, Dec. 19 (UPI) -- A federal appeals court in Washington told the record industry Friday it could no longer issue subpoenas to track down and sue alleged file swappers. Overturning a series of decisions in favor of the Recording Industry Association of America, the court said copyright law did not allow the organization to use subpoenas for the identity of file swappers on Internet service providers' networks, CNET News.com reported."

By the way: downloading pirated music has been legal in Canada the whole time.