When our lightbulbs would burn out, I purchased the Energy Star, energy efficient bulbs. They really do last a LOT longer.
My green bags were my next step. Most places sell them now, and most places have started giving a discount when you use a reusable bag. It doesn't have to be theirs! I found most of them give you $.05 off for each bag you fill. With my two weeks of groceries, I fill between 5-7 bags. I know, it's not much, but it's something!
Mine? I'm going to try making my own cleaning products, and save money that way. Let me know if you have any cheap goals for 2009!