At press previews of the 2008 North American International Auto Show that opens next weekend in Detroit, automakers announced plans to roll out greener vehicles as well as other greenish initiatives. On the hybrid front, market leader Toyota has said it will offer a plug-in hybrid to government and corporate customers by 2010; the plug-in will run on lithium-ion batteries instead of the nickel-metal hydride ones that help power its popular Prius model. Toyota hasn’t yet announced when it expects the plug-ins to be available to the general public, but the news has plug-in enthusiasts salivating. Meanwhile, General Motors has announced it’s invested in a start-up company aiming to produce ethanol from non-corn sources such as wood chips, plastic waste, and trash. The company is also showcasing a Saturn Vue two-mode hybrid at the show.