My local paper has done a few stories like this in the past few weeks. They said that more people are taking the transit bus and train in my area. I have only seen one person on a bike commuting to work at the time I commute. I saw the guy one time, that was it.
Most people are going to grin and bear it until we reach the magic price ( $5, $7, or $10) before they make a major change in their driving habits. They will spend less in other areas. I work with a guy that drives a full size truck, lives 5 miles (2 1/2 miles each way) roundtrip from work. He complains about the price of gas, but won't ride his bike to work.
These stories make it sound easy to just jump on a bike and ride to work. Distance (Anything under 5 miles, most people can do easy), and where you live plays a big part in commuting. I tell everybody that is thinking about commuting to buy slime or thorn resistance tubes, and get the toughest kevlar tires you can afford.