<a href="http://www.realclimate.org/index.php/data-sources/" rel="nofollow">http://www.realclimate.org/index.php/data-sources/</a><p>Data <i>ARE</i> freely available on the web. Basically all of it. 
Sceptics (I hate calling them sceptics: they don't deserve this term) like to repeat they aren't but don't be fooled by them.