From Monty comes an article about some states' plans to turn the gas-tax into a per-mile-driven tax. The reasoning is that hybrid cars drive the same amount, but pay less in gas-tax so the states lose money for road maintenance. I counter-argue that all those gas-guzzling H2's and such on the road will counter that.
At any rate, from the technology perspective, seems the guys at Oregon State University are helping to develop some of the technology to put this together. From the article:
Kim and fellow researcher David Porter at Oregon State University equipped a test car with a global positioning device to keep track of its mileage. Eventually, every car would need one.
Now, if this ever gets put into place, I really need to reconsider building that GPS Jammer.