David Roberts at Gristmill has some carbon tax updates--apparently, it's catching on with everyone who doesn't make the decision! One thing to add is that, since a lot of the aversion to a carbon tax is simply based on an aversion to any tax increase, a grand bargain in the mode of Gore's call to switch all social insurance taxes (FICA, Medicaid) over to a carbon tax might be workable. The downside is that one of the benefits of the tax as a new tax is that you get to spend that money, preferably on stuff that makes the transition easier--subsidies for decarbonized power and public transportation infrastructure, for instance. And one important thing to note is that smartly spent money can have effects far greater than just what you pay for. You can attach strings (to ensure that transit spending is supported by transit-friendly land-use regulations, for example) and you can leverage money (either by requiring matching funds or by funding high quality program or planning design, with implementation paid for by another source).