Birdlife International has expressed some hopes biofuels can indeed help the environment; but is also highly concerned that growing crops for energy could lead to major negative impacts on biodiversity. For instance, farmland birds in Europe are under pressure; and plans to increase oil palmcultivation in se Asia threaten rainforest wildlife.
Brief info, and links to a Birdlife article and some info on a conference:
Unsustainable biofuels threaten the environment