[hga]

This article claims that 3 out of the 4 datasets available, the ones from the CRU, NASA’s Goddard Institute for Space Studies (GISS) and National Climate Data Center Global Historical Climate Network (NCDC GHCN), are not independent and that the latter two were felt by NASA to be inferior to the CRU's. The article doesn't have anything on the raw data, however.

http://pajamasmedia.com/blog/climategate-stunner-nasa-heads-...