Most people will be happy with a very limited agreement in the Doha Round at this point, so pushing for multilateral rules on antitrust/competition policy seems pointless. Nevertheless, antitrust law has become global, with both the U.S and EC regulatory regimes overlapping in a number of ways, and other nations' laws relevant as well. For those interested in teaching/studying antitrust in an international way, there is this new book: Global Antitrust Law and Economics. The authors are Einer Elhauge and Damien Geradin.