In 1992, the EPA and the Department of Energy began a voluntary labeling practice for energy effecient goods, to encourage cost savings and efficiency.
This podcast has an excellent interactive tool to find ways you could save energy in every room of your home. Simple tips like replacing your incandescent bulbs with fluorescent could save the nation as much as $8 billion/annually. Another consideration is a programmable thermostat, which can be set up to adjust yout temperature when you're sleeping or gone from your home.
Take the Energy Star Pledge and find out ways you can save some green and live more green. Like the logo says, Money isn't all you're saving!