Most countries have been focused on the CDM(Clean Development Mechanism). According to Wikipedia, the free encyclopedia, CDM is an arrangement under the Kyoto Protocol allowing industrialized countries with a greenhouse gas reduction commitment to invest in projects that reduce emissions in developing countries as an alternative to more expensive emission reductions in their own countries. There are many environmental problems which resulted from development of IT field. The main objective of this paper is to find an effective methodology as an initial stage for applications of green IT in a real life. Therefore this paper addresses worldwide reviews on green IT products.