Joshua: it IS a good thing to report the bootlegs, and don't let anyone tell you otherwise. :rolleyes
The good thing about eBay is that they at least TRY in most cases to do the right thing. If a seller uses their site as a platform to sell bootlegs, then they will remove that auction if you report it to them. Malcolm's right in that it may not have an effect, since they often have so many reports that it's hard to keep up with. Reporting it tothe studio may help, too...but at least give eBay's reporting a try. It's worked for me several times.
I don't have the ability to provide you with a direct link right now, but eBay has various places that encourage you to report various forms of piracy and other illegal auctions using their "safe harbor" system. Consult their help system for more info.
The Motion Picture Association of America is the industry watchdog for bootlegs and piracy. A relevant excerpt from its web site:
The MPAA maintains a toll-free anti-piracy Hotline number (1-800-NO-COPYS) in the U.S. for retailers and consumers to call if they suspect piracy. In addition, complaints can be directed to the MPAA email hotline at [email protected].