Where to easily get historical bitcoin diffculties?

[ArthurBitcoin]

Where can the exact difficulties of the past months be found?  I know I can read the values off the difficulty charts, but I'm really looking for something like a table of more exact values.  I'm sure this exists... where?

Or some way to get those values? 

[Syke]

This is a pretty good doc.

https://docs.google.com/spreadsheet/ccc?key=0AmcTCtjBoRWUdHVRMHpqWUJValI1RlZiaEtCT1RrQmc