Here's a specific claim by someone who is carefully following one thread of Climategate:
the Wahl and Ammann paper as finally published online on 31 August 2007...was in fact published in 2007, is nothing like the draft seen by the Expert Reviewers, and accordingly should not be referred to in the IPCC 2007 report released in May 2007? Instead the IPCC should have reflected the published peer-reviewed literature and concluded that the 2001 IPCC hockey stick was statistically invalid.
David Holland, the author of this quote filed a freedom of information request,asking (as far as I can tell) for information relating to the publication of this paper. Two days later, UEA Director Prof Phil Jones asked Professor Michael Mann (lead author of the "hockey stick") to tell his ex student Ammann to delete these emails. According to Holland, this is what leaked email 1212063122 is about.
There's something VERY suspicious about asking anyone to ask anyone else to delete emails that have been requested under a Freedom of Information Act request. Watergate was just a "third rate burglary" that toppled a president. Climategate could turn out to be even bigger.