These folks have started a website where people can sign up to indicate how many CFL's they have purchased to replace standard incandescent light bulbs. The mission is to save people money and the world's energy by getting 1,000,000,000 light bulbs changed over.
So far they have enough members signed up that they have tracked over 170,000 changed bulbs around the world. Over 148,000 of those have come from the United States alone.
We switched over just about every single bulb in our home with a CFL as soon as the incandescent burned out. The exceptions to this are overhead lights where 1. CFL does not fit or 2. Can not be installed for safety issues. We have 4 floor lamps and 4 overhead lights where CFL's can be utilized and have changed over all the lamps at this time.
To date, those 4 replaced bulbs are calculated at the One Billion Bulbs site to save us $52.84 and 443 lbs of greenhouse gas (CO2) annually (at an approximate 4 hour usage per bulb per day). Now that's savings I can get behind!
I hope everyone has a chance to not only check out the site, and sign up to record your own activity, but to also replace as many of your own bulbs with compact fluorescents as possible to save money and the planet!