CAMBRIDGE, — Green IT is all the rage at the moment, from companies launching green data centers to environment-themed expos at CeBIT in Germany.

This trend is only going to increase -- dramatically so -- according to researchers at Forrester, who predict that green IT consulting services will boom from the roughly $500 million market in 2008 to $4.8 billion five years from now.

Behind this explosive growth is a herd of companies large and small that have not even begun to plan a strategy to move toward energy-efficient data centers and employee workstations. Only 6 percent of company representatives who responded to a survey by Forrester said they had brought on outside help for planning the switch.

The Forrest report, "The Dawn of Green IT Services," suggests that OEMs like Dell, HP and Intel will benefit at the start of this boom, as their data center services take root, but closer to the end of the five-year project, bigger-picture service providers like Accenture, Deloitte and IBM will benefit most by applying their "holistic perspective" to company-wide efficiency efforts.