While there is no coherent national plug-in vehicle legislation aside from the PHEV tax credit bill, some states are moving forward with their own proposals to encourage more vehicles with plugs. Both Colorado and Illinois recently passed plug-in support laws.
In Colorado, House Bill 1331, the "Incentives for Efficient Motor Vehicles" act, creates or extends tax credits for natural gas conversions, plug-in hybrid conversions, diesel-electric hybrid conversions (don't see many of those) and also supports anti-idling technologies. The credits are maxed out at $6,000 and you can find full details here. H.B. 1331 recently passed the Colorado State House and Senate and was then signed by the Governor.
Meanwhile, over in Illinois, Governor Pat Quinn has signed a bill that gives almost $250 million to various technology projects in the state, including $10 million for "electric car infrastructure." The Chicago Sun Times says the money "could help Illinois develop manufacturing and/or research-and-development offices for the next generation of automobiles." For comparison: the bill also included $7 million for "an advanced protein crystallization facility." Just saying.
Now, where is the federal support?