If you want to step back and look at some of the basics, here are some good sources:
This from the Pew Center on Global Climate Change.
From the Intergovernmental Panel on Climate Change (IPCC), the Summary for Policymakers of the Synthesis Report from the Fourth Assessment Report.
From the United Nations Framework Convention on Climate Change (UNFCCC), Feeling the Heat.
You can also go to the BBC Weather Centre's site on climate change for some clear, simple basics.