Right now you can get free energy saving light bulbs in Victoria and New South Wales. There is no maximum number of lightbulbs to replace, but you need to replace a minimum of three.
The energy saving light bulbs are available for free because the company that replaces the original light bulbs with energy saving light bulbs gets paid for the carbon emissions saved by installing the energy saving light bulbs.
You can apply for your free light bulbs at the following web-site:
The company that is providing the free light bulbs is approved as “Greenhouse Friendly” by the Australian government, so it looks legit. You need to book a visit from one of their “installers” to get the bulbs for free, but as long as all they are doing is installing the energy saving lightbulbs, then it hopefully won’t be too much hastle.
If you live in Sydney and don’t want to bother with the hastle of an installer then check out this offer, which can let you pickup five free energy saving lightbulbs. (Please note that as of 2011 this free offer is no longer valid.)