This sharply designed site houses a number of tools. After a simple registration process, users can calculate carbon emissions and how many trees are needed to offset those emissions. Take it a step further and purchase trees to offset those emissions. Future Forests will plant trees on your behalf in various forests throughout the world. It conducts assessments of a corporation's carbon production and helps determine the number of trees to plant and the location. Its Web site profiles companies that are trying to go carbon neutral: Avis, BT, Imagination, Mazda, Glastonbury Festival, and Fulham Football Club.