http://www.climatecare.org/
Climate Care is an organisation which funds projects with the specific aim of making reductions in carbon dioxide and other greenhouse gas concentrations, in order to reduce climate change..
http://www.carbonneutral.com/
The Carbon Neutral company works for individuals who want to tackle climate change.  Their core services are carbon consulting and carbon offsetting – both designed to help reduce CO2 emissions, and deliver commercial, personal and environmental benefit.