The U.S. and the E.U. will cooperate in joint hydrogen research, according to this New York Times article (registration required) and this Associated Press article.
And on the emissions front, if you take into account emissions of carbon dioxide, an MIT study finds that hybrid engines pollute less than hydrogen engines. The study indicates that hydrogen vehicles are unlikely to improve on hybrid vehicles in terms of total energy use and greenhouse gas emissions until after 2020. Their analysis reflects the fact that battery production and gasoline use in combination, compared with the process of reforming hydrogen from natural gas using platinum as a catalyst, requires the expenditure of less energy to create the fuel. Furthermore, hydrogen vehicles emit carbon dioxide and water vapor, and are therefore not going to satisfy a policy that is supposed to address greenhouse gases.