The PHEV Prius will have lithium-ion batteries (finally!) and an electric range of 20 km (12.4 miles), with a top speed in electric mode of 100 kph (62 mph). CO2 emissions should be around 60g/km.
12 miles all-electric isn't exactly earth-shattering, but okay for trips around town. What caught my eye was the CO2 emissions. The 2nd generation Prius produces 104 g/km of CO2, so a reduction down to 60 g/km is really good (though you have to add the emissions from the power grid, which should be relatively low). It makes me wonder under what conditions they estimated that 60 g/km though - like how many miles before recharging. Still, reducing emissions by about 40% from an already low emissions car is pretty impressive.
They're supposed to introduce 500 of the plug-in Priuses to fleets and such in 2010. No word on when the rest of us can get one. I suspect 2012.