Below is a link to a (conservative) political satire site. The author has taken a break from his usual work to put together an excellent how-to guide for understanding the statistical models for climate studies and how they WORK. Highly recommended.
This is just a link to an interesting (and very detailed) technical analysis for this issue. It is very marginally critical of Mann, et.al., nothing too far-out or snippy, IMHO. Be sure to Post any rebuttals to his conclusions on HIS site.