I've cited this article before. I think he sums it up better than I can.

http://www.junkscience.com/Greenhouse/index.html

The spectral absorbency part really gets me. CO2 is an an already saturated absorbency range. Adding more material will not absorb more energy.

Not to mention data like this: http://mysite.verizon.net/mhieb/WVFossils/tempCO2_vs_solwind.html

To which the author writes something to the effect of, "wow, our CO2 is so powerful it even controls the energy output of the sun".

To assume that global warming is a "problem" you have to first say that now is the BEST climate we could have. Then, you have to look at the data... I mean really look at a lot of data and then realized, "oh crap... all this data... really does not tell me that much... the earth's history is much longer than our data series". So, the only thing we really know is that we don't know enough.

More fun:
http://m2.aol.com/gregbenson/iceage.htm
http://www.xtronics.com/reference/globalwarming.htm

I want a bumper sticker that says, "it's the water vapor stupid"
http://mysite.verizon.net/mhieb/WVFossils/greenhouse_data.html

GW is caused by pirates (or lack there of)!!
http://www.seanbonner.com/blog/archives/001857.php

-A good story-
An engineer is out walking in the park and sees a wild-eyed man hitting a strangely painted block of wood with a stick. The engineer's curiosity gets the better of him, so he asks the wild-eyed man, "Why are you hitting that block?"
The wild-eyed man replies with a bit of a crazed smile, "The sound keeps the elephants away."
The engineer, now fully intrigued, digs deeper, "But why? There are no elephants here."
As the wild-eyed man continues to make his noise with renewed vigor, he says, "See! It's working."