Many times, these denier sites all quote one study, and in the cacophony confusion arises.
I would like to add that often these sites quote a study that does not say what the site claims it says, usuallly the contrary. So always check out the study, too. If you don't know the lingo, or can follow the science, there's usually some discussion to be found handling the misquoting of the paper.
As there very seldom is "conclusive" studies in anything -- and especially so in a cross-discipline field covering physics, astronomy and biology -- you'd be better off starting with Spencer Wearth's Discovery of Global Warming, me thinks.
A list is only as strong as its weakest link. -- Don Knuth