Some quick links before I go back to sleep [1].
It seems that Anthony Watts [2] is questioning the collection of tempurature data [3] and that the data is showing urban heat islands [4] and not necessarily global warming.
I got the link from Flutterby, which has some further commentary and links [5] about this phenomenon (do do de do do [6]) that's worth reading up on as well.
[2] http://www.norcalblogs.com/watts/
[3] http://www.norcalblogs.com/watts/weather_stations/
[4] http://en.wikipedia.org/wiki/Urban_heat_island
[5] https://boston.conman.org/