If you haven't made up your mind and want to see how McCain and Obama are on climate change and the environment, some of this material might help you. If you have made up your mind, this stuff might give you an idea of how President Obama or President McCain might pursue matters of the environment and energy.
The excellent "Nature Reports , Climate Change" had a news feature last month, US elections: the candidates on climate. The campaigns responded to a number of very good questions such as "In order to reach a global climate change agreement in Copenhagen in 2009, do you believe that the United States should take the lead on signing up to international binding emissions targets? And how should the United States proceed if China and India do not initially agree to such a mandate?" The good folks at "Nature" also know very well how dependent any solutions in the US are on how Congress grapples with the complex and politically thorny issues at hand. I've written here a great deal about Congress and climate change, energy, and the environment, most recently about the draft cap-and-trade proposal in the House and the wild ride that the tax credits for renewables had. See US elections: Challenges in Congress from "Nature." See also this thoughtful editorial from their Olive Heffernan.
There's also this very good summary of the Presidential candidates' positions from the "NY Times" and Andy Revkin, as well as this head-to-head look at key facets of the important questions on climate change.