Were the Russians forewarned about North Korea's impending test?  Particularly, did they know telling details like the size of the device that Kim Jong Il's regime set off?  And how might they have acquired sensitive information?

There is evidence to suggest they did know quite a bit more than they're admitting to.  But they apparently didn't know enough details to keep quiet when the test, practically speaking, fizzled.  Nor, converesly, did they choose to share what they knew with their good friend, America. In spite of President Bush's assessment of his relationship with Mr. Putin,

And the more I get to know President Putin, the more I get to see his heart and soul, and the more I know we can work together in a positive way.  White House News

it appears that five years into their "special friendship," Mr. Putin doesn't hold Mr. Bush in the same regard.