Interesting idea. But I suspect that getting rid of a second car wouldn't save as much gas as you might think. You'd definitely be ahead from the standpoint of car payment/insurance, though.
Most of the families I know with two cars would do nearly the same amount of driving with one car. People still have to get to work, shop, take kids to soccer, etc.
I expect to see more emphasis on carpooling if the gas prices stay high.
For a lot of people, the gas prices don't mean squat and they won't conserve. I know a guy with four drivers in their home and they have four cars. They also have two boats, two ATVs, and a riding lawnmower. He's come right out and told me that he can afford to burn $100 in gas a day riding his boat around, and he has no plans to cut back.